Palo Alto PAN-OS flaw CVE-2026-0321 allows unauthenticated denial-of-service via dataplane traffic

Palo Alto Networks released a batch of security advisories in mid-October 2026, which CERT-FR grouped under advisory CERTFR-2026-AVI-1326. Most issues in the batch require local or administrative access, but CVE-2026-0321 stands apart because an unauthenticated attacker with network reach can send crafted traffic to a dataplane interface. Repeated exploitation can trigger a denial-of-service state that pushes the device into maintenance mode. The flaw is rated MEDIUM at 6.6 under CVSS 4.0, reflecting its availability-only impact rather than the ease of exploitation. Analysts recommend handling it on a separate, shorter timeline from the rest of the batch, since its effect is on traffic rather than credentials.