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CVE-2026-0227: GlobalProtect's Glass Jaw: Bricking Firewalls with CVE-2026-0227

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GlobalProtect's Glass Jaw: Bricking Firewalls with CVE-2026-0227

Vulnerability ID: CVE-2026-0227
CVSS Score: 7.5
Published: 2026-01-15

CVE-2026-0227 is a deceptively simple Denial of Service (DoS) vulnerability in Palo Alto Networks' GlobalProtect that weaponizes the system's own safety mechanisms against it. By sending malformed HTTP requests to the GlobalProtect portal or gateway, an unauthenticated attacker can crash the gpsvr process. While a single crash is a minor annoyance, a persistent attack triggers the firewall's internal watchdog to assume a hardware failure, forcing the entire device into 'Maintenance Mode'. This results in a complete cessation of network traffic and requires manual, physical intervention to restore, effectively turning a software bug into a physical denial of service.

TL;DR

Unauthenticated attackers can send malformed packets to GlobalProtect, crashing the service. If repeated, the firewall enters 'Maintenance Mode' and stops passing traffic, requiring a physical reboot to fix.

⚠️ Exploit Status: POC

Technical Details

  • CWE: CWE-754: Improper Check for Unusual Conditions
  • Attack Vector: Network (AV:N)
  • CVSS v3.1: 7.5 (High)
  • EPSS Score: 0.00071 (Low/Emerging)
  • Impact: System Availability (Maintenance Mode)
  • Exploit Status: PoC Available

Affected Systems

  • PAN-OS 12.1
  • PAN-OS 11.2
  • PAN-OS 11.1
  • PAN-OS 10.2
  • PAN-OS 10.1
  • Prisma Access
  • PAN-OS 12.1: < 12.1.3-h3, < 12.1.4 (Fixed in: 12.1.3-h3)
  • PAN-OS 11.2: < 11.2.4-h15 (Fixed in: 11.2.4-h15)
  • PAN-OS 11.1: < 11.1.4-h27 (Fixed in: 11.1.4-h27)
  • PAN-OS 10.2: < 10.2.10-h30 (Fixed in: 10.2.10-h30)

Exploit Details

  • GitHub: Fingerprinting and Scanner Script
  • GitHub: Advanced Scanner for CVE-2026-0227

Mitigation Strategies

  • Apply vendor patches immediately.
  • Restrict GlobalProtect interface access to trusted IPs where feasible.
  • Monitor system logs for repeated 'gpsvr' process restarts.

Remediation Steps:

  1. Identify current PAN-OS version via Dashboard or CLI (show system info).
  2. Compare against the affected version list (e.g., < 11.1.4-h27).
  3. Download the relevant patch release from the Palo Alto Networks support portal.
  4. Schedule a maintenance window (ironic, considering the bug causes one anyway).
  5. Install the update and reboot the device.

References

Read the full report for CVE-2026-0227 on our website for more details including interactive diagrams and full exploit analysis.

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