CVE-2026-0300 - Critical Buffer Overflow in PAN-OS User-ID Authentication Portal
On May 6, 2026, Palo Alto Networks disclosed a critical buffer overflow vulnerability (CVE-2026-0300) in the User-ID Authentication Portal (Captive Portal) component of PAN-OS. This vulnerability allows an unauthenticated, remote attacker to execute arbitrary code with root privileges on affected PA-Series and VM-Series firewalls by sending specially crafted packets. No user interaction or credentials are required.