9.3
Critical
Exploited
CVE-2026-0300 Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
Active exploitation observed
· CISA KEV catalogue
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Until the vendor releases an official fix, the following workaround should be implemented: - Restrict User-ID Authentication Portal access to only trusted zones. - Disable User-ID Authentication Portal if not required. 5/13/2026: Palo Alto has released a variety of patches. If these are relevant to your environment, please apply the designated patch.
Ransomware campaigns
Not observed so far
Weakness
CWE-787
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Cloud NGFW | Versions not published | |
| PAN-OS 12.1 | 12.1.0 → < 12.1.7 | 12.1.7 |
| PAN-OS 11.2 | 11.2.0 → < 11.2.12 | 11.2.12 |
| PAN-OS 11.1 | 11.1.0 → < 11.1.15 | 11.1.15 |
| PAN-OS 10.2 | 10.2.0 → < 10.2.18-h6 | 10.2.18-h6 |
| Prisma Access | Versions not published | |
| RUGGEDCOM APE1808 | Versions not published |
References
- security.paloaltonetworks.com security.paloaltonetworks.com
Timeline
- Published
- Added to the KEV catalogue
- Last modified
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The 114 CVEs of Cloud NGFW →
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