CVE-2026-77711

Severity: high (CVSS 8.2 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-15 · updated 2026-10-15
Weakness: CWE-200

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.

Affected products

The Eclipse Foundation Eclipse Jetty: from 12.1.0 through 12.1.12; from 12.0.0 through 12.0.38; from 11.0.0 through 11.0.32; from 10.0.0 through 10.0.32; from 9.4.0 through 9.4.64

References

https://github.com/jetty/jetty.project/security/advisories/GHSA-r2c5-3p8g-wpvw
https://gitlab.eclipse.org/security/cve-assignment/-/work_items/238
https://github.com/jetty/jetty.project/security/advisories/GHSA-r2c5-3p8g-wpvw

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