Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 06/05/2026. Patch affected systems as an emergency.
| Package | Affected versions | Patched versions |
|---|---|---|
| PAN-OS | Versions not published yet (product named by CISA KEV) | |
A buffer overflow vulnerability in the User-ID™ Authentication Portal (aka Captive Portal) service of Palo Alto Networks PAN-OS software allows an unauthenticated attacker to execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls by sending specially crafted packets. The risk of this issue is greatly reduced if you secure access to the User-ID™ Authentication Portal per the best practice guidelines https://knowledgebase.paloaltonetworks.com/KCSArticleDetail by restricting access to only trusted internal IP addresses. Prisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.
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