Bug 2459390 (CVE-2026-40490)

Summary: CVE-2026-40490 async-http-client: AsyncHttpClient: Credential leakage via improper handling of authorization headers during redirects
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: asoldano, bbaranow, bmaxwell, bstansbe, dlofthou, fmariani, gmalinko, istudens, ivassile, iweiss, janstey, mosmerov, msvehla, nwallace, pberan, pdelbell, pesilva, pjindal, pmackay, rstancel, rstepani, smaestri, tcunning, thjenkin, vdosoudi, yfang
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in AsyncHttpClient. When redirect following is enabled, the library improperly forwards Authorization and Proxy-Authorization headers, including Realm credentials, to arbitrary redirect targets regardless of domain, scheme, or port changes. An attacker who controls a redirect target can exploit this to capture sensitive credentials, such as Bearer tokens and Basic authentication credentials. This information disclosure occurs on cross-domain redirects and when downgrading from HTTPS to HTTP.
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Description OSIDB Bzimport 2026-04-18 02:01:19 UTC
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.