Insufficient Certificate Checks in OCaml-TLS Client Implementation
CVE-2026-45388

9.1CRITICAL

Key Information:

Vendor

OCaml

Status
OCaml-TLS
Vendor
CVE Published:
15 June 2026

What is CVE-2026-45388?

The OCaml-TLS library, prior to version 2.1.0, suffers from a security flaw where the client component does not adequately validate server-provided certificates. This oversight can lead to potential impersonation attacks using certificates not intended for server authentication, as specified by KeyUsage and ExtendedKeyUsage attributes. Organizations utilizing this library should consider upgrading to the latest version to mitigate risks associated with these weaknesses.

References

https://osv.dev/vulnerability/OSEC-2026-06

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.