CVE-2026-45388

Critical severity, CVSS 9.1. EPSS: 0.3% chance of exploitation in the next 30 days.

In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication (because of KeyUsage and ExtendedKeyUsage).

Published 2026-06-15. Last modified 2026-06-17.