CVE-2026-0300
CRITICAL
9,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A
Description
AI Translation Available
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.
787
Out-of-bounds Write
DraftCommon Consequences
Security Scopes Affected:
Integrity
Availability
Other
Potential Impacts:
Modify Memory
Execute Unauthorized Code Or Commands
Dos: Crash, Exit, Or Restart
Unexpected State
Applicable Platforms
Languages:
Assembly, C, C++, Memory-Unsafe
Technologies:
ICS/OT
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026…
https://security.paloaltonetworks.com/CVE-2026-0300