CVE-2026-0300
PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal
KEVCRITICAL 9.3EPSS 31.7%
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.
- Affected
- Palo Alto Networks · PAN-OS
- CVSS v4.0 PALOALTONETWORKS
- 9.3 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N/E:A/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:C/RE:M/U:Red - CVSS v3.1 NVD
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 31.72% chance of exploitation in the next 30 days, 98th percentile
- CISA KEV
- added 2026-05-06
- Published
- 2026-05-06
- Updated
- 2026-10-15
Proof-of-concept exploits (7)
- p3Nt3st3r-sTAr/CVE-2026-0300-POC22★ · 2026-05-07
- matad0r-maghribi/CVE-2026-0300-PANOS4★ · 2026-05-06
- 0xBlackash/CVE-2026-03001★ · 2026-05-06
- shizuku198411/CVE-2026-03001★ · 2026-05-06
- qassam-315/PAN-OS-User-ID-Buffer-Overflow-PoC3★ · 2026-05-06
- lu4m575/CVE-2026-03000★ · 2026-05-21
- sam00/POC-CVE-2026-0300-exploit0★ · 2026-08-06
Security advisories
- https://security.paloaltonetworks.com/CVE-2026-0300
- https://cert-portal.siemens.com/productcert/html/ssa-967325.html