Vulnerability Description
The crypton-x509-validation Haskell library fails to enforce X.509 NameConstraints, allowing TLS clients to accept certificates whose Subject Alternative Names fall outside the issuing CA’s permitted subtrees. This oversight enables an attacker who compromises a name-constrained sub-CA to impersonate domains beyond its intended scope.
CVSS Score
CRITICAL
References
- https://github.com/haskell/security-advisories/pull/332
- https://github.com/kazu-yamamoto/crypton-certificate/pull/30
- https://github.com/kazu-yamamoto/crypton-certificate/pull/30/changes/f4b77edf6ea
- https://hackage.haskell.org/package/crypton-x509-validation-1.9.1/revisions/
- https://www.kb.cert.org/vuls/id/862559
FAQ
What is CVE-2026-9648?
CVE-2026-9648 is a vulnerability with a CVSS score of 9.1 (CRITICAL). The crypton-x509-validation Haskell library fails to enforce X.509 NameConstraints, allowing TLS clients to accept certificates whose Subject Alternative Names fall outside the issuing CA’s permitted ...
How severe is CVE-2026-9648?
CVE-2026-9648 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-9648?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.