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.
| Vendor | Product | Versions |
|---|---|---|
| palo alto networks | pan-os | 12.1.0, 11.2.0, 11.1.0, 10.2.0 |
Downstream vendors/products affected by this vulnerability
| Vendor | Product | Source | Confidence |
|---|---|---|---|
| palo alto networks | pa-1410 | cve_cpe | 95% |
| palo alto networks | pa-1420 | cve_cpe | 95% |
| palo alto networks | pa-3410 | cve_cpe | 95% |
| palo alto networks | pa-3420 | cve_cpe | 95% |
| palo alto networks | pa-3430 | cve_cpe | 95% |
Updated description with new technical details, changed severity to CRITICAL, and added new IoCs EarthWorm and ReverseSocks5.
Updated description with details about exploitation, added CVE-2026-0300, changed severity to CRITICAL, updated patch availability to May 13, and added 'zero-day' tag.
Updated severity to HIGH, CVSS score to 9.3, added new CWE, and included new tags related to critical and espionage.
Updated description with technical details, changed vendor and product names, updated severity to HIGH, added CVSS estimate of 7.5, included new CWE IDs, confirmed exploit availability, and added IOC and MITRE ATT&CK information.
Updated description with critical vulnerability details, changed severity to CRITICAL, and noted that there is no exploit available.
Initial creation
