CVE-2026-13122 - Server assert via malformed auth-token with external-auth

OpenVPN version 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers to cause a denial of service via a malformed authentication token that triggers a reachable assertion when external-auth is enabled.

CVE Record: CVE-2026-13122

Github:

• OpenVPN/openvpn-private-issues#118

Release notes:

• openvpn-2.7.5
• openvpn-2.6.21

Reported-By: Haiyang Huang (huanghaiyang83@gmail.com)