The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.14.5 to 2.16.0 and from 3.0.9 to 3.0.11, a client configured with a client-wide Realm and redirect following can disclose credentials after a cross-origin redirect because the Interceptors authentication path falls back to the client configuration after redirect handling clears the per-exchange realm. If the attacker-controlled target returns 401, the client can send Basic or Digest credentials or a Negotiate or NTLM token to that origin. Per-request realms are stripped correctly, and this issue is a residual bypass of the earlier cross-origin credential-stripping fixes. This issue is fixed in versions 2.16.1 and 3.0.12.

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

### Impact A client configured with a client-wide realm (a Realm set on the config builder rather than on an individual request) and following redirects could re-send those credentials to a redirect target on a different origin. The redirect code strips the per-exchange realm, but when the target answered 401 the credentials were re-derived from the client config, handing Basic or Digest credentials, or a Negotiate or NTLM token, to an attacker controlled origin. This is a residual of the earlier cross-origin credential leak advisories, whose strip this bypassed.

### Affected versions * 3.x: 3.0.9 through 3.0.11 * 2.x: 2.14.5 through 2.16.0

Releases below those floors are covered by the earlier advisories GHSA-cmxv-58fp-fm3g and GHSA-fmxf-pm6p-7xgm: the cross-origin strip that this issue bypasses did not exist yet, so the leak there is the original one rather than this residual.

### Patches Fixed in 3.0.12 on the 3.x line and in 2.16.1 on the 2.x line. The realm is taken from the per-exchange state that the redirect already cleared, rather than being re-derived from the client configuration.

### Workarounds Set the Realm on the individual request instead of on the client configuration. A per-request realm is stripped correctly on a cross-origin redirect while still authenticating same-origin, so this is a complete workaround with no loss of function. Turning off follow-redirects also avoids it. Note that setStripAuthorizationOnRedirect(true) is not a workaround: it force…

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 2.14.5 to 2.16.0 and from 3.0.9 to 3.0.11, a client configured with a client-wide Realm and redirect following can disclose credentials after a cross-origin redirect because the Interceptors authentication path falls back to the client configuration after redirect handling clears the per-exchange realm. If the attacker-controlled target returns 401, the client can send Basic or Digest credentials or a Negotiate or NTLM token to that origin. Per-request realms are stripped correctly, and this issue is a residual bypass of the earlier cross-origin credential-stripping fixes. This issue is fixed in versions 2.16.1 and 3.0.12.