CVE-2026-9648: Haskell Programming Language Crypton-Certificate

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

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.

Affected products

• Haskell Programming Language Crypton-Certificate: before 1.9.1 (fixed in 1.9.1)

Published 2026-06-11. Last modified 2026-06-17.