CVE-2026-0300Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
CISA Known Exploited Vulnerabilities Data
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.
CISA Due Date
May 9, 2026 (federal agency requirement)
Known Ransomware Campaign Use
Unknown
Notes
https://security.paloaltonetworks.com/CVE-2026-0300 ; https://nvd.nist.gov/vuln/detail/CVE-2026-0300
External References
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Data sourced from the CISA Known Exploited Vulnerabilities catalog. CISA does not endorse any commercial product or service.