CVE-2026-0300
KEVPalo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
9.3
CriticalPublished:
Last updated:
Source:psirt@paloaltonetworks.com
Analyzed
Weakness (CWE)
CVSS Vector
v4.0- Attack Vector
- Network
- Attack Complexity
- Low
- Attack Requirements
- None
- Privileges Required
- None
- User Interaction
- None
- Confidentiality (Vulnerable)
- High
- Integrity (Vulnerable)
- High
- Availability (Vulnerable)
- High
- Confidentiality (Subsequent)
- Low
- Integrity (Subsequent)
- Low
- Availability (Subsequent)
- None
Description
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.
References
psirt@paloaltonetworks.com
https://security.paloaltonetworks.com/CVE-2026-03000b142b55-0307-4c5a-b3c9-f314f3fb7c5e
https://cert-portal.siemens.com/productcert/html/ssa-967325.html134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-0300