CVE-2026-404906.8MediumCWE-200

CVE-2026-40490: AsyncHttpClient leaks authorization credentials to untrusted domains on cross-origin redirects

AsyncHttpClient · async-http-client

Affected: AsyncHttpClient async-http-client · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.4%probability of exploitation in the next 30 days

36th percentile

050100

Higher than 36% of scored CVEs

6.8MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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 products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

AsyncHttpClient · async-http-client>= 3.0.0.Beta1, < 3.0.9; < 2.14.5

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Information Exposure · Information Disclosure
Vendor: AsyncHttpClient
Published: April 2026
Band: Unlikely (under 1%), April 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-40490 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.