Out-of-bounds write in Palo Alto PAN-OS - CVE-2026-0300
Published: May 6, 2026
Vulnerability identifier: #VU130217
CSH Severity: Critical
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/U:Red
CVE-ID: CVE-2026-0300
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerable software:
Palo Alto PAN-OS
Palo Alto PAN-OS
Software vendor:
Palo Alto Networks, Inc.
Palo Alto Networks, Inc.
Description
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a boundary error within the User-ID Authentication Portal (aka Captive Portal) service. A remote attacker can send specially crafted packets to the device, trigger an out-of-bounds write and execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls.
Note, the vulnerability is being actively exploited in the wild.
Remediation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.
Vendor plans to release fixes on May 13 and May 28.