When Jetty's `HttpClient` make a request to a server through a forward proxy, the server may reply with a 407 (Proxy Authentication Required). The client mistakenly interprets the 407 as coming from the proxy, so it re-sends the request with the `Proxy-Authentication` header, which arrives to the server, that now has access to the proxy credentials.
History

Mon, 19 Oct 2026 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Eclipse
Eclipse jetty
Vendors & Products Eclipse
Eclipse jetty

Fri, 16 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
Title org.eclipse.jetty/jetty-client: jetty-client: Information disclosure via improper proxy authentication handling
Weaknesses CWE-201
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

threat_severity

Important


Thu, 15 Oct 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 15 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
Description When Jetty's `HttpClient` make a request to a server through a forward proxy, the server may reply with a 407 (Proxy Authentication Required). The client mistakenly interprets the 407 as coming from the proxy, so it re-sends the request with the `Proxy-Authentication` header, which arrives to the server, that now has access to the proxy credentials.
Weaknesses CWE-200
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: eclipse

Published: 2026-10-15T08:51:48.066Z

Updated: 2026-10-15T13:50:52.566Z

Reserved: 2026-08-21T08:58:54.421Z

Link: CVE-2026-77711

cve-icon Vulnrichment

Updated: 2026-10-15T13:50:46.699Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-15T09:17:18.573

Modified: 2026-10-15T14:41:34.110

Link: CVE-2026-77711

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-15T08:51:48Z

Links: CVE-2026-77711 - Bugzilla