CVE-2026-45389
Client-auth bypass vulnerability in OCaml-TLS permits impersonation.
Is CVE-2026-45389 being exploited?
Not confirmed. CVE-2026-45389 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.19% probability of exploitation in the next 30 days.
How severe is CVE-2026-45389?
CVE-2026-45389 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-45389?
Yes. A fix has been recorded for CVE-2026-45389. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-45389 affect?
CVE-2026-45389 affects OCaml-TLS <= 2.1.0. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-45389?
Upgrade to 2.1.0+
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Bypass client authentication to impersonate a client during TLS handshake, granting unauthorized access.
Patch when possible