Executive brief
The AsyncHttpClient (AHC) library, a popular tool for Java applications to handle web requests, contains a flaw that leaks sensitive user information. When an application is redirected from a trusted site to a different website, the library fails to remove security cookies from the request. This allows an attacker who controls a redirect destination to steal session cookies, login credentials, or API keys, potentially leading to account takeover or data theft.
Technical details
A sensitive information disclosure vulnerability exists in AsyncHttpClient (AHC) due to improper header sanitization during HTTP redirects. The 'propagatedHeaders()' method in 'Redirect30xInterceptor.java' is designed to strip sensitive headers like 'Authorization' when a request is redirected to a different origin or downgraded from HTTPS to HTTP. However, it fails to remove the 'Cookie' header. An attacker can exploit this by inducing a redirect to a malicious domain, which will then receive the original site's session cookies. This vulnerability affects versions 2.x prior to 2.15.0 and 3.x prior to 3.0.10. Patches are available in versions 2.15.0 and 3.0.10.
Affected products
- AsyncHttpClient AsyncHttpClient (AHC) >= 2.0.0, < 2.15.0; >= 3.0.0.Beta1, < 3.0.10
Timeline
- 2026-05-12: patched: Versions 2.15.0 and 3.0.10 released
- 2026-06-05: disclosed: CVE-2026-45300 published