CVE-2026-0227
7.5 HIGH
📋 TL;DR
An unauthenticated attacker can send specially crafted requests to Palo Alto Networks PAN-OS firewalls, causing them to crash and enter maintenance mode. This denial-of-service vulnerability affects all organizations running vulnerable PAN-OS versions on their firewalls.
💻 Affected Systems
Products:
- Palo Alto Networks PAN-OS
Versions: Specific versions not provided in CVE description - check vendor advisory
Operating Systems: PAN-OS (custom OS)
Default Config Vulnerable:
⚠️ Yes
Notes: Affects firewalls with management interfaces exposed to untrusted networks. All PAN-OS firewalls running vulnerable versions are affected regardless of configuration.
📦 What is this software?
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Prisma Access by Paloaltonetworks
⚠️ Risk & Real-World Impact
Worst Case
Firewall becomes completely unavailable, requiring manual intervention to restore service, potentially disrupting all network traffic through the device.
Likely Case
Firewall enters maintenance mode after repeated exploitation attempts, causing network outages until manually recovered.
If Mitigated
Firewall remains operational with proper network segmentation and access controls limiting exposure to unauthenticated requests.
🌐 Internet-Facing: HIGH - Unauthenticated attackers can directly target internet-facing firewalls without any credentials.
🏢 Internal Only: MEDIUM - Internal attackers or compromised internal systems could exploit this, but requires network access to firewall management interfaces.
🎯 Exploit Status
Public PoC:
✅ No
Weaponized:
UNKNOWN
Unauthenticated Exploit:
⚠️ Yes
Complexity:
LOW
CWE-754 indicates improper check for unusual or exceptional conditions, suggesting relatively straightforward exploitation once the specific trigger is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific fixed versions
Vendor Advisory: https://security.paloaltonetworks.com/CVE-2026-0227
Restart Required: Yes
Instructions:
1. Check vendor advisory for affected versions. 2. Download and install the latest PAN-OS version that addresses CVE-2026-0227. 3. Schedule maintenance window for firewall restart. 4. Apply update following Palo Alto Networks upgrade procedures.
🔧 Temporary Workarounds
Restrict Management Interface Access
allLimit access to firewall management interfaces to trusted IP addresses only
Configure management interface ACLs to allow only authorized management stations
Enable Management Interface Protection
allUse Palo Alto Networks security policies to protect management interfaces
Apply security policies to management interface with strict source/destination restrictions
🧯 If You Can't Patch
- Implement strict network segmentation to isolate firewall management interfaces from untrusted networks
- Deploy intrusion prevention systems (IPS) or web application firewalls (WAF) in front of management interfaces to detect and block exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check PAN-OS version against affected versions listed in vendor advisoryCheck Version:
show system info | match versionVerify Fix Applied:
Verify PAN-OS version is updated to a version that addresses CVE-2026-0227 as specified in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by system entering maintenance mode
- Unexpected firewall restarts or maintenance mode entries
Network Indicators:
- Unusual traffic patterns to firewall management interfaces from untrusted sources
- Sudden drop in firewall traffic processing
SIEM Query:
source="pan-firewall" AND (event_type="system" AND message="entering maintenance mode") OR (event_type="threat" AND action="deny" AND dst_port IN (443, 22, 80))