CVE-2021-3056: Palo Alto Networks PAN-OS

High severity, CVSS 8.8. EPSS: 1.5% chance of exploitation in the next 30 days.

A memory corruption vulnerability in Palo Alto Networks PAN-OS GlobalProtect Clientless VPN enables an authenticated attacker to execute arbitrary code with root user privileges during SAML authentication. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.9; PAN-OS 10.0 versions earlier than PAN-OS 10.0.1. Prisma Access customers with Prisma Access 2.1 Preferred firewalls are impacted by this issue.

Affected products

• Palo Alto Networks PAN-OS: from 8.1.0, before 8.1.20 (fixed in 8.1.20); from 9.0.0, before 9.0.14 (fixed in 9.0.14); from 9.1.0, before 9.1.9 (fixed in 9.1.9); version 10.0.0 only

Published 2021-11-10. Last modified 2026-06-17.