CVE-2026-85720 AsyncHttpClient: Origin credentials sent to the proxy on the plaintext CONNECT request
Attackers can intercept origin credentials sent in plaintext during proxy CONNECT requests, exposing sensitive authentication data to proxies and network observers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-85720?
CVE-2026-85720 is a medium-severity vulnerability in AsyncHttpClient async-http-client, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12.
Which versions are affected by CVE-2026-85720?
4 open source packages ship an affected version, including org.asynchttpclient:async-http-client.
| Package | Affected | Fixed in |
|---|---|---|
org.asynchttpclient:async-http-client Maven | From 2.0.0 | 2.16.1 |
org.asynchttpclient:async-http-client Maven | From 2.0.0 | 2.16.1 |
org.asynchttpclient:async-http-client Maven | From 3.0.0 | 3.0.12 |
org.asynchttpclient:async-http-client Maven | From 3.0.0 | 3.0.12 |
How do I fix CVE-2026-85720?
Upgrade org.asynchttpclient:async-http-client to a fixed version for your release line: 2.16.1 or 3.0.12.
Is CVE-2026-85720 being exploited?
There is no known exploitation of CVE-2026-85720 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-85720, ECHO-085c-5da2-0e78, GHSA-xr57-gcx8-52hf, MINI-76xm-5pmc-73pp, MINI-77qw-pcch-mrr4, MINI-jfr8-2v76-mx22 and 2 more.