CVE-2021-3063: Palo Alto Networks PAN-OS

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

An improper handling of exceptional conditions vulnerability exists in Palo Alto Networks GlobalProtect portal and gateway interfaces that enables an unauthenticated network-based attacker to send specifically crafted traffic to a GlobalProtect interface that causes the service to stop responding. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.21; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14-h4; PAN-OS 9.1 versions earlier than PAN-OS 9.1.11-h3; PAN-OS 10.0 versions earlier than PAN-OS 10.0.8-h4; PAN-OS 10.1 versions earlier than PAN-OS 10.1.3. Prisma Access customers are not impacted by this issue.

Affected products

• Palo Alto Networks PAN-OS: from 8.1.0, before 8.1.21 (fixed in 8.1.21); from 9.0.0, up to and including 9.0.14; from 9.1.0, up to and including 9.1.11; from 10.0.0, up to and including 10.0.8; from 10.1.0, before 10.1.3 (fixed in 10.1.3)

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