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

Palo Alto Networks PAN-OS

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. Added to CISA KEV on 2026-05-06 (federal deadline 2026-05-09).

First seen: 6 May 2026
Last update: 6 May 2026, 12:00 UTC
Identifiers: CVE-2026-0300
Source: CISA KEV
On the menu as: VPN & firewalls

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
Severity: high, exploited in the wild. Patch status: patched.
Affected: Palo Alto Networks PAN-OS
Ids: CVE-2026-0300

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. Added to CISA KEV on 2026-05-06 (federal deadline 2026-05-09).

## Steps
1. This touches infrastructure (vpn-edge). Look in terraform, ansible, cloud-init, Dockerfiles and docs for the product and version we run. If it isn't in the repo, say so and list what a human should check on the box.

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-0300") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://nvd.nist.gov/vuln/detail/CVE-2026-0300 https://security.paloaltonetworks.com/CVE-2026-0300
https://pwned.coffee/i/palo-alto-networks-pan-os-out-of-bounds-write-vulnerabil-cve-2026-0300

Sources

Totalone hot coffee