Update dependency org.asynchttpclient:async-http-client to v2.16.0 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
org.asynchttpclient:async-http-client	2.12.4 → 2.16.0

---

AsyncHttpClient leaks authorization credentials to untrusted domains on cross-origin redirects

CVE-2026-40490 / GHSA-cmxv-58fp-fm3g

More information

Details

Impact

When redirect following is enabled (followRedirect(true)), AsyncHttpClient forwards 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.

Patches

Fixed in version 3.0.9 or 2.14.5. Users should upgrade immediately.

The fix 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.

Workarounds

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 or 2.14.5 because the Realm bypass still re-generates credentials.

Alternatively, disable redirect following (followRedirect(false)) and handle redirects manually with origin validation.

References

• Fix commit: AsyncHttpClient/async-http-client@6b2fbb7f8

Severity

• CVSS Score: 6.8 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

References

• https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
• https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8
• https://nvd.nist.gov/vuln/detail/CVE-2026-40490
• 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/advisories/GHSA-cmxv-58fp-fm3g

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

async-http-client: Cookie header not stripped on cross-origin redirect

CVE-2026-45300 / GHSA-fmxf-pm6p-7xgm

More information

Details

Summary

async-http-client leaks Cookie headers to cross-origin redirect targets. When following a redirect across a security boundary (different origin, or HTTPS→HTTP downgrade), the propagatedHeaders() method in Redirect30xInterceptor.java strips Authorization and Proxy-Authorization headers but does not strip Cookie, so session cookies and other sensitive cookie values are forwarded to the redirect target — which may be attacker-controlled.

Details

The vulnerability is in client/src/main/java/org/asynchttpclient/netty/handler/intercept/Redirect30xInterceptor.java.

The caller computes stripAuth on each redirect:

boolean sameBase    = request.getUri().isSameBase(newUri);
boolean stripAuth   = !sameBase || schemeDowngrade || stripAuthorizationOnRedirect;
// ...
requestBuilder.setHeaders(propagatedHeaders(request, realm, keepBody, stripAuth));

stripAuth is true whenever the redirect crosses an origin, downgrades the scheme, or the caller opted in via AsyncHttpClientConfig#isStripAuthorizationOnRedirect().

In the vulnerable version, propagatedHeaders() only removes Authorization and Proxy-Authorization in that branch — Cookie is left untouched:

private static HttpHeaders propagatedHeaders(Request request, Realm realm, boolean keepBody, boolean stripAuthorization) {
    HttpHeaders headers = request.getHeaders()
            .remove(HOST)
            .remove(CONTENT_LENGTH);

    if (!keepBody) {
        headers.remove(CONTENT_TYPE);
    }

    if (stripAuthorization || (realm != null && (realm.getScheme() == AuthScheme.NTLM
            || realm.getScheme() == AuthScheme.SCRAM_SHA_256))) {
        headers.remove(AUTHORIZATION)
                .remove(PROXY_AUTHORIZATION);
        // BUG: COOKIE is not removed here, so cookies leak across the security boundary.
    }
    return headers;
}

The companion test class RedirectCredentialSecurityTest covers Authorization / Proxy-Authorization stripping on cross-origin redirects and scheme downgrades, but has no coverage for Cookie, which is why the regression went unnoticed.

Proof of concept

import org.asynchttpclient.*;

AsyncHttpClient client = asyncHttpClient();

// trusted-api.com responds 302 -> https://evil.com
Request request = new RequestBuilder("GET")
        .setUrl("https://trusted-api.com/endpoint")
        .setHeader("Cookie", "session=abc123; csrf=xyz789; api_key=secret")
        .setHeader("Authorization", "Bearer token123")
        .build();

client.executeRequest(request).get();

// Request seen by evil.com after the redirect:
//   Authorization: <stripped>
//   Cookie:        session=abc123; csrf=xyz789; api_key=secret   <-- leaked

Impact

• Session hijacking — leaked session cookies allow impersonation.
• CSRF token theft — CSRF tokens carried in cookies are disclosed.
• API key theft — API keys stored in cookies are disclosed.
• Privacy — tracking identifiers leak to third-party origins.

Realistic attack paths:

• Open-redirect in a trusted API endpoint.
• Compromised CDN or API gateway injecting redirects.
• MITM on a plaintext hop in the redirect chain.

Fix

Add COOKIE to the headers removed alongside AUTHORIZATION / PROXY_AUTHORIZATION on the security-boundary branch:

if (stripAuthorization) {
    headers.remove(AUTHORIZATION)
            .remove(PROXY_AUTHORIZATION)
            .remove(COOKIE);
} else if (realm != null && (realm.getScheme() == AuthScheme.NTLM
        || realm.getScheme() == AuthScheme.SCRAM_SHA_256)) {
    headers.remove(AUTHORIZATION)
            .remove(PROXY_AUTHORIZATION);
}

Note that the URI-scoped CookieStore will re-add any cookies that legitimately match the new target after propagatedHeaders returns, so legitimate cross-origin sessions tracked by the client are not broken.

Fixed in 3.0.10 and 2.15.0 by commit 3b0e3e9e.

Severity

• CVSS Score: 7.4 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N

References

• https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-fmxf-pm6p-7xgm
• https://github.com/AsyncHttpClient/async-http-client/commit/3b0e3e9e
• https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.10
• https://nvd.nist.gov/vuln/detail/CVE-2026-45300
• https://github.com/advisories/GHSA-fmxf-pm6p-7xgm

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

AsyncHttpClient stores cookie for an unrelated domain (cookie tossing) via ThreadSafeCookieStore

CVE-2026-55688 / GHSA-m452-q8c9-rg2f

More information

Details

Impact

A cookie tossing / cookie injection issue (CWE-1275). ThreadSafeCookieStore stored a cookie under the value of its Domain attribute without verifying that the responding host is allowed to set a cookie for that domain (RFC 6265 §5.3 step 6). A host the client connects to can therefore plant a cookie scoped to an unrelated domain, and the client will then send that cookie on later requests to that domain.

Who is Impacted

Applications that use a single AsyncHttpClient instance - and thus the default, shared CookieStore - to reach both an attacker-influenced host and a trusted host. Typical exposure: crawlers, link-preview / webhook fetchers, SSRF-style "fetch this URL" features, multi-backend aggregators, or following redirects to an attacker-controlled host. The attacker can write a cookie the client presents to the victim host (session fixation, overwriting a session id / CSRF-token cookie); they cannot read the victim host's cookies. Applications that talk only to a fixed trusted backend, or that disable/scope the cookie store, are not exposed.

Patches

Fixed in 3.0.11 and 2.16.0

Workarounds

• Disable the cookie store (setCookieStore(null)) when cookies are not needed; or
• Use a separate AsyncHttpClient (separate cookie store) per trust domain so an attacker-influenced host and a trusted host never share a jar
• Supply a custom CookieStore whose add(Uri, Cookie) rejects cookies whose Domain is not domain-matched by the request host.

Severity

• CVSS Score: 4.0 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

References

• https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-m452-q8c9-rg2f
• https://nvd.nist.gov/vuln/detail/CVE-2026-55688
• https://github.com/AsyncHttpClient/async-http-client/pull/2196
• https://github.com/AsyncHttpClient/async-http-client/pull/2199
• https://github.com/AsyncHttpClient/async-http-client/commit/8e4069cf3c92abe099db5fb13378ac2fe9e1fd3b
• https://github.com/AsyncHttpClient/async-http-client/commit/e6955c1e3951cf80e286981d064f6c926ce33f47
• https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.16.0
• https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.11
• https://lists.debian.org/debian-lts-announce/2026/08/msg00011.html
• https://github.com/advisories/GHSA-m452-q8c9-rg2f

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Configuration

📅 Schedule: (UTC)

• Branch creation
  • At any time (no schedule defined)
• Automerge
  • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.