CVE-2026-45389: n/a
In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client (when doing client authentication), which allows impersonation with certificates that are not meant for client authentication (because of KeyUsage and ExtendedKeyUsage).
AI Analysis
Technical Summary
CVE-2026-45389 affects OCaml-TLS versions prior to 2.1.0. The server's client authentication process fails to adequately check the KeyUsage and ExtendedKeyUsage extensions of client certificates. As a result, certificates that are not meant for client authentication can be accepted, enabling impersonation attacks. This vulnerability is categorized under CWE-295 (Improper Certificate Validation). The CVSS v3.1 base score is 7.4, indicating a high severity with network attack vector, high attack complexity, no privileges required, no user interaction, unchanged scope, and high confidentiality and integrity impact.
Potential Impact
An attacker can impersonate a legitimate client by presenting a certificate that lacks proper client authentication usage attributes. This undermines the trust model of client authentication in OCaml-TLS, potentially leading to unauthorized access or data disclosure. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid relying on OCaml-TLS versions prior to 2.1.0 for client certificate authentication or implement additional certificate validation checks externally to ensure proper KeyUsage and ExtendedKeyUsage enforcement.
CVE-2026-45389: n/a
Description
In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client (when doing client authentication), which allows impersonation with certificates that are not meant for client authentication (because of KeyUsage and ExtendedKeyUsage).
CVSS v3.1
Score 7.4high
Affected software
pkg:golang/github.com/mirleft/ocaml-tlsRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-45389 affects OCaml-TLS versions prior to 2.1.0. The server's client authentication process fails to adequately check the KeyUsage and ExtendedKeyUsage extensions of client certificates. As a result, certificates that are not meant for client authentication can be accepted, enabling impersonation attacks. This vulnerability is categorized under CWE-295 (Improper Certificate Validation). The CVSS v3.1 base score is 7.4, indicating a high severity with network attack vector, high attack complexity, no privileges required, no user interaction, unchanged scope, and high confidentiality and integrity impact.
Potential Impact
An attacker can impersonate a legitimate client by presenting a certificate that lacks proper client authentication usage attributes. This undermines the trust model of client authentication in OCaml-TLS, potentially leading to unauthorized access or data disclosure. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid relying on OCaml-TLS versions prior to 2.1.0 for client certificate authentication or implement additional certificate validation checks externally to ensure proper KeyUsage and ExtendedKeyUsage enforcement.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-05-12T00:00:00.000Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3052e10b89be688882748f
Added to database: 06/15/2026, 19:30:41 UTC
Last enriched: 06/23/2026, 14:58:24 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 48
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