Vulnerability · Published Apr 18, 2026 · Assigned by GitHub_M
CVE-2026-40490AsyncHttpClient leaks authorization credentials to untrusted domains on cross-origin redirects
Medium 6.8
In plain English
A medium-severity information exposure in async-http-client from AsyncHttpClient. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. When redirect following is enabled (followRedirect(true)), versions of AsyncHttpClient prior to 3.0.9 and 2.14.5 forward Authorization and Proxy-Authorization headers along with Realm credentials to arbitrary redirect targets regardless of domain, scheme, or port changes. This leaks credentials on cross-domain redirects and HTTPS-to-HTTP downgrades. Additionally, even when stripAuthorizationOnRedirect is set to true, the Realm object containing plaintext credentials is still propagated to the redirect request, causing credential re-generation for Basic and Digest authentication schemes via NettyRequestFactory. An attacker who controls a redirect target (via open redirect, DNS rebinding, or MITM on HTTP) can capture Bearer tokens, Basic auth credentials, or any other Authorization header value. The fix in versions 3.0.9 and 2.14.5 automatically strips Authorization and Proxy-Authorization headers and clears Realm credentials whenever a redirect crosses origin boundaries (different scheme, host, or port) or downgrades from HTTPS to HTTP. For users unable to upgrade, set `(stripAuthorizationOnRedirect(true))` in the client config and avoid using Realm-based authentication with redirect following enabled. Note that `(stripAuthorizationOnRedirect(true))` alone is insufficient on versions prior to 3.0.9 and 2.14.5 because the Realm bypass still re-generates credentials. Alternatively, disable redirect following (`followRedirect(false)`) and handle redirects manually with origin validation.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | async-http-client | no fix listed | DEBIAN-CVE-2026-40490 |
| Maven | org.asynchttpclient:async-http-client | 3.0.9 | GHSA-cmxv-58fp-fm3g |
| Maven | org.asynchttpclient:async-http-client | 2.14.5 | GHSA-cmxv-58fp-fm3g |
| Ubuntu:22.04:LTS | async-http-client | no fix listed | UBUNTU-CVE-2026-40490 |
| Ubuntu:24.04:LTS | async-http-client | no fix listed | UBUNTU-CVE-2026-40490 |
| Ubuntu:25.10 | async-http-client | no fix listed | UBUNTU-CVE-2026-40490 |
| Ubuntu:26.04:LTS | async-http-client | no fix listed | UBUNTU-CVE-2026-40490 |
| Ubuntu:26.10 | async-http-client | no fix listed | UBUNTU-CVE-2026-40490 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| AsyncHttpClient | async-http-client | >= 3.0.0.Beta1, < 3.0.9< 2.14.5 |
Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
References
- https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g x_refsource_CONFIRM
- https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8 x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5 x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9 x_refsource_MISC