CVE-2026-54147
http4k is a functional toolkit for Kotlin HTTP applications. Prior to 4.51.0.0, 5.42.0.0, and 6.50.0.0, DigestAuthProvider.verify in http4k-security-digest ignores its configured algorithm parameter and verifies every Digest response with hardcoded MD5. Deployments configured for SHA-256 therefore receive weaker MD5-based verification, exposing Digest authentication to collision-related attack paths that depend on the hash function's collision resistance. This issue is fixed in versions 4.51.0.0, 5.42.0.0, and 6.50.0.0.
- Published Sep 18, 2026
- CVSS 6.5 medium
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available