Vulnerability in Eclipse Foundation Eclipse Jetty

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official 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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund15 Oct 2026WID-SEC-2026-3992

  Eclipse Jetty: Multiple vulnerabilities Translated from German

  Risk highCVE-2026-18661CVE-2026-76184CVE-2026-19864+4 more CVEs

[ References ]References

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