CVE-2026-77711

high

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.

References

https://gitlab.eclipse.org/security/cve-assignment/-/work_items/238

https://github.com/jetty/jetty.project/security/advisories/GHSA-r2c5-3p8g-wpvw

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-101947

Details

Source: Mitre, NVD

Published: 2026-10-15

Updated: 2026-10-15

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base 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

Severity: High

EPSS

EPSS: 0.0032