{"cve":"CVE-2026-40490","nvd":{"published":"2026-04-18T02:16:11.977","modified":"2026-06-17T10:45:22.360","status":"Deferred","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","score":6.8},"cwes":["CWE-200"],"references":["https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8","https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae","https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5","https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9","https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:30:49.762551342+00:00"},"epss":{"cve":"CVE-2026-40490","score":0.00415,"percentile":0.35786,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-cmxv-58fp-fm3g","url":"https://osv.dev/vulnerability/GHSA-cmxv-58fp-fm3g","summary":"AsyncHttpClient leaks authorization credentials to untrusted domains on cross-origin redirects","modified":"2026-09-10T03:50:43.967987263Z","packages":[{"ecosystem":"Maven","name":"org.asynchttpclient:async-http-client","purl":"pkg:maven/org.asynchttpclient/async-http-client","ranges":[">=3.0.0.Beta1 <3.0.9"],"fixed":["3.0.9"]},{"ecosystem":"Maven","name":"org.asynchttpclient:async-http-client","purl":"pkg:maven/org.asynchttpclient/async-http-client","ranges":[">=2.0.0 <2.14.5"],"fixed":["2.14.5"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}