An authentication bypass vulnerability in the Large Scale VPN (LSVPN) feature of Palo Alto Networks PAN‑OS allows an attacker with network access to forge authentication messages and establish an unauthorized site‑to‑site VPN tunnel. The flaw does not provide arbitrary code execution but creates a back‑door channel that could be used for covert communication or data exfiltration between otherwise isolated networks.

Affected releases include PAN‑OS 10.2.0 through 7, PAN‑OS 11.1.0 through 11.1.15, PAN‑OS 11.2.0 through 11.2.12, and PAN‑OS 12.1.0 through 12.1.7-h7. Panorama, Cloud NGFW, and Prisma Access are not impacted.

The CVSS v3 base score of 4.5 indicates moderate severity, and the EPSS score of less than 1% suggests a low likelihood of exploitation in the wild. The vulnerability requires only network‑level access and does not involve privileged local access or code execution. It is not listed in the CISA KEV catalog.