High severity · published Oct 15, 2026
CVE-2026-77711
When Jetty's `HttpClient` make a request to a server through a forward proxy, the server may reply with a 407 (Proxy Authentication Required)
8.2
CVSS
0.4%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EJ
Eclipse Jetty · Eclipse Foundation
12.1.0 through 12.1.12; 12.0.0 through 12.0.38; 11.0.0 through 11.0.32; 10.0.0 through 10.0.32; 9.4.0 through 9.4.64 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77711
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77711
github.com
https://github.com/jetty/jetty.project/security/advisories/GHSA-r2c5-3p8g-wpvw
gitlab.eclipse.org
https://gitlab.eclipse.org/security/cve-assignment/-/work_items/238
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