Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
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.
- Vendor
- Palo Alto Networks
- Product
- PAN-OS
- CVSS
- 9.8
- EPSS (exploit probability)
- 32.1%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Published
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.
Added to CISA’s Known Exploited Vulnerabilities catalog on 2026-05-06. Required action per CISA: 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. Due date: 2026-05-09.
This is an auto-synced KEV catalog record pending a full 0dayNews write-up — see CISA’s KEV catalog and the NVD record linked above for primary sources.