Http4s: DigestAuth allows replay of captured requests

NVD Description

The `DigestAuth` replay defence stores `lastNc + 1` rather than the nonce-count (`nc`) value it just accepted. When a legitimate client sends non-contiguous `nc` values (parallel or retried requests, as browsers do), the server's counter lags behind the highest `nc` seen, and a captured `Authorization` header can be replayed multiple times. ## Impact A passive observer can turn one captured Digest-authenticated request into several replayed authenticated (state-changing) requests, defeating the core replay protection Digest provides over Basic. ## Preconditions - Application uses `DigestAuth`. - Attacker can passively observe at least one legitimate digest request. - Legitimate client emits an `nc` more than one greater than the last, for instance from a parallel or retried request. ## Workarounds - Deploy over TLS so requests cannot be captured.

Affected Packages (3)