CVE-2026-0300
Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
// Description
Palo Alto Networks PAN-OS contains an out-of-bounds write vulnerability in the User-ID Authentication Portal (aka Captive Portal) service that can allow an unauthenticated attacker to execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls by sending specially crafted packets.
// Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Until the vendor releases an official fix, the following workaround should be implemented: - Restrict User-ID Authentication Portal access to only trusted zones. - Disable User-ID Authentication Portal if not required. 5/13/2026: Palo Alto has released a variety of patches. If these are relevant to your environment, please apply the designated patch.
Federal remediation due May 9, 2026 — past due
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// Coverage
- CVE-2026-0300: Siemens RUGGEDCOM APE1808 RCE via PAN-OS Vulnerability
May 19, 2026
- PAN-OS RCE via CVE-2026-0300 — Mitigation Guide
May 7, 2026
- CVE-2026-0300: Palo Alto Networks PAN-OS Out-of-bounds Write Exploit
May 6, 2026
- CVE-2026-0300: Critical Zero-Day in PAN-OS Captive Portal Service
May 6, 2026