CVE-2026-0203

6.5 MEDIUM

📋 TL;DR

An unauthenticated attacker on an adjacent network can send a specially crafted malformed ICMPv4 packet to vulnerable Juniper Junos OS devices, causing the Forwarding Plane Card (FPC) to crash and restart, resulting in a denial of service. This affects multiple Junos OS versions across various release trains. The attack is limited to adjacent networks because upstream routers won't forward the malformed packet.

💻 Affected Systems

Products:
  • Juniper Networks Junos OS
Versions: All versions before 21.2R3-S9, 21.4 before 21.4R3-S10, 22.2 before 22.2R3-S7, 22.3 before 22.3R3-S4, 22.4 before 22.4R3-S5, 23.2 before 23.2R2-S3, 23.4 before 23.4R2-S3, 24.2 before 24.2R1-S2, 24.2R2
Operating Systems: Junos OS
Default Config Vulnerable: ⚠️ Yes
Notes: Only affects ICMPv4 processing. ICMPv6 is not vulnerable. Requires network adjacency to target device.

📦 What is this software?

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete network disruption as FPC crashes cause routing failures and traffic loss until restart completes, potentially affecting multiple devices if attacker targets multiple interfaces.

🟠

Likely Case

Temporary service interruption on affected interfaces during FPC restart, causing packet loss and connectivity issues for 30-60 seconds per crash.

🟢

If Mitigated

Minimal impact with proper network segmentation and access controls preventing adjacent attacker access to vulnerable devices.

🌐 Internet-Facing: LOW - Attack requires adjacent network access and malformed packets won't be forwarded by upstream routers.
🏢 Internal Only: MEDIUM - Internal adjacent attackers (compromised devices, malicious insiders) could disrupt critical network infrastructure.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ⚠️ Yes
Complexity: LOW - Requires crafting specific malformed ICMP packet but no authentication needed.

Exploitation requires network adjacency and knowledge of specific malformed packet structure. No public exploit code identified in references.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 21.2R3-S9, 21.4R3-S10, 22.2R3-S7, 22.3R3-S4, 22.4R3-S5, 23.2R2-S3, 23.4R2-S3, 24.2R1-S2 (or later)

Vendor Advisory: https://kb.juniper.net/JSA104294

Restart Required: Yes

Instructions:

1. Check current Junos OS version with 'show version'. 2. Download appropriate fixed version from Juniper support. 3. Follow standard Junos upgrade procedure: backup config, transfer image, install package, reboot. 4. Verify upgrade with 'show version'.

🔧 Temporary Workarounds

ICMP Rate Limiting

all

Apply rate limiting to ICMP packets to reduce impact of potential attacks

set firewall family inet filter ICMP-RATE-LIMIT term 1 from protocol icmp
set firewall family inet filter ICMP-RATE-LIMIT term 1 then policer 1m-icmp
set firewall policer 1m-icmp if-exceeding bandwidth-limit 1m
set firewall policer 1m-icmp if-exceeding burst-size-limit 15k
set firewall policer 1m-icmp then discard

Interface ACL Blocking

all

Apply access control lists to limit ICMP from untrusted adjacent networks

set firewall family inet filter BLOCK-ICMP term 1 from protocol icmp
set firewall family inet filter BLOCK-ICMP term 1 then discard
set interfaces <interface> unit 0 family inet filter input BLOCK-ICMP

🧯 If You Can't Patch

  • Implement strict network segmentation to limit adjacent device access to vulnerable Junos devices
  • Deploy intrusion prevention systems (IPS) with signatures for malformed ICMP packet detection and blocking

🔍 How to Verify

Check if Vulnerable:

Run 'show version' and compare against affected version ranges listed in advisory. Check if device processes ICMPv4 traffic.

Check Version:

show version | match Junos

Verify Fix Applied:

After upgrade, verify version is patched with 'show version'. Monitor FPC stability with 'show chassis fpc' during ICMP traffic.

📡 Detection & Monitoring

Log Indicators:

  • FPC crash messages in system logs
  • ICMP packet discard logs from firewall filters
  • Unexpected FPC restarts in chassis logs

Network Indicators:

  • Spike in malformed ICMP packets from single source
  • Unusual ICMP traffic patterns to network infrastructure

SIEM Query:

source="junos-log" AND ("FPC" AND "crash" OR "restart") OR ("ICMP" AND "malformed" OR "discard")

🔗 References

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