CVE-2026-21906
📋 TL;DR
An unauthenticated attacker can crash the packet forwarding engine on vulnerable Juniper SRX Series devices by sending a specific ICMP packet through a GRE tunnel when PowerMode IPsec and GRE performance acceleration are enabled. This causes traffic loss during PFE restart. Affected systems include Junos OS on SRX Series with specific vulnerable versions and configurations.
💻 Affected Systems
- Juniper Networks SRX Series
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Denial of service causing extended network outages, repeated crashes leading to sustained traffic loss, and potential bypass of security controls during PFE restart.
Likely Case
Temporary traffic disruption during PFE restart, requiring manual intervention if crashes recur, with service restoration after PFE reboot.
If Mitigated
Minimal impact if workarounds are applied or vulnerable configurations are disabled, with no exploitation possible from properly filtered traffic.
🎯 Exploit Status
Exploitation requires sending specific ICMP packet through GRE tunnel to vulnerable configuration. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S5, 24.2R2-S3, 24.4R2-S1, 25.2R1-S1 (or later)
Vendor Advisory: https://kb.juniper.net/JSA106005
Restart Required: Yes
Instructions:
1. Check current Junos OS version. 2. Download appropriate fixed version from Juniper support. 3. Backup configuration. 4. Install update following Juniper upgrade procedures. 5. Reboot device to apply changes.
🔧 Temporary Workarounds
Disable GRE Performance Acceleration
allTurn off GRE performance acceleration feature that triggers the vulnerability when combined with PowerMode IPsec
delete security powermode ipsec gre-acceleration
Filter ICMP Traffic on GRE Tunnels
allBlock or rate-limit ICMP packets on GRE tunnel interfaces using firewall filters
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 st0 unit 0 family inet filter input BLOCK-ICMP
🧯 If You Can't Patch
- Disable GRE performance acceleration immediately
- Implement strict ICMP filtering on GRE tunnel interfaces
🔍 How to Verify
Check if Vulnerable:
Check if running vulnerable Junos version AND if GRE performance acceleration is enabled: show configuration security powermode ipsec | match gre-accelerationCheck Version:
show version | match JunosVerify Fix Applied:
Verify Junos version is patched: show version | match Junos AND confirm GRE acceleration is disabled or ICMP filtering is active📡 Detection & Monitoring
Log Indicators:
- PFE crash/restart messages in system logs
- ICMP packet drops on GRE interfaces
- Traffic loss alerts
Network Indicators:
- ICMP packets to GRE tunnel endpoints
- Unusual ICMP traffic patterns
- Service disruption on SRX devices
SIEM Query:
source="juniper-srx" AND ("PFE" AND (crash OR restart)) OR ("ICMP" AND "GRE")