CVE-2026-40490
AsyncHttpClient leaks authorization credentials to untrusted domains on cross-origin redirects
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.8 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.8 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.41% · top 64% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.8.
Weakness
Affected products
AsyncHttpClient · async-http-client
- affected >= 3.0.0.Beta1, < 3.0.9
- affected < 2.14.5
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenorg.asynchttpclient:async-http-clientGHSA-cmxv-58fp-fm3g (opens in a new tab)
References (5)
- https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g (opens in a new tab)x_refsource_CONFIRM
- https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8 (opens in a new tab)x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae (opens in a new tab)x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5 (opens in a new tab)x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-cmxv-58fp-fm3g (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-40490)Record last updated .