CVE-2026-100834

http4k's Digest authentication module (org.http4k:http4k-security-digest) before versions 6.48.0.0, 5.42.0.0 and 4.51.0.0 defaults the nonceVerifier parameter of ServerFilters.DigestAuth and DigestAuthProvider to { true }, so every nonce is accepted regardless of its value, age, or prior use. Applications relying on this default have no replay protection on Digest authentication: an attacker who can capture a valid 'Authorization: Digest' response (for example by observing network traffic or reading logs) can replay it indefinitely against the same protected resource.

• https://github.com/http4k/http4k/commit/4f904b4692
• https://github.com/http4k/http4k/commit/8a52b615b1
• https://github.com/http4k/http4k/security/advisories/GHSA-c7jm-38gq-h67h
• https://www.vulncheck.com/advisories/http4k-before-6.48.0.0-digest-authentication-replay-protection-bypass