CVE-2026-0300 - Palo Alto Networks PAN-OS
AI Vulnerability ContextA 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 pract...
Overview
A source-backed snapshot of this vulnerability.
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.
Vulnerability status
How serious this vulnerability is and whether it is known to be exploited.
- CVE ID
- CVE-2026-0300
- Vendor/project
- Palo Alto Networks
- Product
- PAN-OS
- Vulnerability name
- Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
- Date added
- 2026-05-06
- Due date
- 2026-05-09
- Known ransomware campaign use
- Unknown
- CVSS v3
- 9.8
- CVSS v4
- 9.3
Exploit context
What the vulnerability is about.
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.
Source evidence
Original public records and references for this page.
Original source
Original source links
Open the public records and source datasets used for this page.