CVE-2021-3053: Palo Alto Networks PAN-OS

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

An improper handling of exceptional conditions vulnerability exists in the Palo Alto Networks PAN-OS dataplane that enables an unauthenticated network-based attacker to send specifically crafted traffic through the firewall that causes the service to crash. 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 8.1.20; 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 10.0.5. This issue does not affect Prisma Access.

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); from 10.0.0, before 10.0.5 (fixed in 10.0.5)

Published 2021-09-08. Last modified 2026-06-17.