Critical PAN-OS Vulnerability Demands Immediate Attention

Joint advisory on CVE-2026-0300: a critical (CVSS 9.3) out-of-bounds buffer overflow in Palo Alto Networks PA-Series and VM-Series PAN-OS (10.2, 11.1, 11.2, 12.1) targeting the USER-ID authentication portal that can yield unauthenticated root access. Limited exploitation has been observed in education, healthcare, and ISP sectors; patches are not expected until at least May 13. Immediate recommendations include monitoring inbound traffic on ports 6080–6082 for anomalous HTTP POSTs (notably oversized Content-Length to /php/uid.php), isolating inbound traffic, using allow lists, monitoring for suspicious outbound connections from firewalls, and applying Palo Alto Threat Prevention signatures and community detection rules when available.