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CVE-2026-0300

Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability

Palo Alto Networks PAN-OSNetwork & edge
Open in ThreatlineRecord JSON
CVSS
9.3Critical
ExploitationExploited in the wildAdded to KEV 6 May 2026CISA KEV
Exploit odds (EPSS)31.7%Chance of exploitation activity in the next 30 days, higher than 98% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in12.1.7Also 11.2.12, 11.1.15 and 1 moreCVE List
Federal deadline9 May 2026Remediation due date for US federal agenciesCISA KEV
CISA required actionApply 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. CISA KEV

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

  1. 6 May 2026Added to CISA KEVCISA KEV
  2. 6 May 2026, 18:57 UTCPublishedCVE List

Description

Palo Alto Networks PAN-OS contains an out-of-bounds write vulnerability in the User-ID Authentication Portal (aka Captive Portal) service that can allow an unauthenticated attacker to execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls by sending specially crafted packets.

Text from CVE List

Affected versions 6

  • Cloud NGFWunaffected: AllCVE List
  • PAN-OSaffected: 12.1.0 before 12.1.7CVE List
  • PAN-OSaffected: 11.2.0 before 11.2.12CVE List
  • PAN-OSaffected: 11.1.0 before 11.1.15CVE List
  • PAN-OSaffected: 10.2.0 before 10.2.18-h6CVE List
  • Prisma Accessunaffected: AllCVE List

References 4