CVE-2026-85720

AsyncHttpClient: Origin credentials sent to the proxy on the plaintext CONNECT request

Published Sep 17, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xr57-gcx8-52hf AsyncHttpClient sends origin credentials to the proxy on the plaintext CONNECT request
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Asynchttpclient Project
Asynchttpclient Project async-http-client
Vendors & Products Asynchttpclient Project
Asynchttpclient Project async-http-client
Type Values Removed Values Added
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.
Title AsyncHttpClient: Origin credentials sent to the proxy on the plaintext CONNECT request
Weaknesses CWE-319
CWE-522
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 21, 2026, 8:52 PM
Reserved
Sep 4, 2026, 2:45 PM
Status
Awaiting Analysis
Published
Sep 17, 2026, 5:16 PM
Modified
Sep 24, 2026, 9:16 PM