CVE-2026-77711

org.eclipse.jetty/jetty-client: jetty-client: Information disclosure via improper proxy authentication handling

Published Oct 15, 2026 CVSS 4.0 · 8.2 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Eclipse
Eclipse jetty
Vendors & Products Eclipse
Eclipse jetty
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

Type Values Removed Values Added
Metrics ssvc

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
eclipse
Published
Updated
Oct 15, 2026, 1:50 PM
Reserved
Aug 21, 2026, 8:58 AM
Status
Awaiting Analysis
Published
Oct 15, 2026, 9:17 AM
Modified
Oct 15, 2026, 2:41 PM
Severity
Important
Public date
Oct 15, 2026, 8:51 AM