The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 3.0.8 until 3.0.12, processScramAuthenticationInfo and processAuthenticationInfo compute the SCRAM ServerSignature or Digest rspauth verification result but log a mismatch and still deliver the response as authenticated. On a non-TLS or compromised transport, a peer that has not proved knowledge of the shared secret can therefore be accepted as the server. The fix rejects a present invalid value and computes Digest rspauth from the Authorization parameters actually sent, but verification remains unenforced when the value is absent, the sent parameters cannot be recovered, or Digest uses qop=auth-int. This issue is fixed in version 3.0.12.

Affected: Maven: org.asynchttpclient:async-http-client

### Impact For SCRAM, and for Digest with mutual authentication, the client computes the server's verification value (the SCRAM ServerSignature, or the Digest rspauth) but does not act on the result. If the value is present and does not verify, the client only logs it and still delivers the response to the application as a successful, authenticated result. A server that never proved knowledge of the shared secret is accepted, so the client loses its ability to detect an impostor. Over TLS the real server always returns a valid value and the issue is inert; it matters over a non TLS transport, or when the transport is already compromised, where it removes the client's only signal that the peer does not know the secret.

### Affected versions * 3.x: 3.0.8 through 3.0.11

Earlier 3.0.x releases are not affected: neither SCRAM nor the Digest Authentication-Info handling existed before 3.0.8. The 2.x line is not affected either: it has no SCRAM support, and its interceptor chain does not implement Digest mutual authentication, so there is no verification result to act on.

### Patches Fixed in 3.0.12. A present ServerSignature (SCRAM) or rspauth (Digest) that does not verify now fails the request instead of being logged and ignored, on both the origin and proxy paths.

### Known limitations Verification is only enforced when the value is present and the parameters the client sent can be recovered. A response that omits the Authentication-Info header entirely, or that carries the…

Affected: Ubuntu:Pro:14.04:LTS: async-http-client, Ubuntu:16.04:LTS: async-http-client, Ubuntu:18.04:LTS: async-http-client, Ubuntu:Pro:20.04:LTS: async-http-client, Ubuntu:22.04:LTS: async-http-client, Ubuntu:24.04:LTS: async-http-client, Ubuntu:26.04:LTS: async-http-client

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 3.0.8 until 3.0.12, processScramAuthenticationInfo and processAuthenticationInfo compute the SCRAM ServerSignature or Digest rspauth verification result but log a mismatch and still deliver the response as authenticated. On a non-TLS or compromised transport, a peer that has not proved knowledge of the shared secret can therefore be accepted as the server. The fix rejects a present invalid value and computes Digest rspauth from the Authorization parameters actually sent, but verification remains unenforced when the value is absent, the sent parameters cannot be recovered, or Digest uses qop=auth-int. This issue is fixed in version 3.0.12.