{"id":"CVE-2026-125109","published":"2026-11-09T22:18:42.127","lastModified":"2026-11-10T17:17:26.000","description":"Rack is a modular Ruby web server interface. From 3.0 until 3.1.23 and 3.2.8, Rack::Request#host_with_port, #base_url, and #url can return an attacker-controlled invalid authority from Host, X-Forwarded-Host, or Forwarded: host= verbatim. Applications without an independent host allowlist that use these methods for absolute URLs, redirects, or origin-dependent checks can emit attacker-chosen delimiters, enabling redirect manipulation, string-based allowlist bypass, or unescaped markup reflection. Rails overrides these methods and is not expected to be affected. This issue is fixed in versions 3.1.23 and 3.2.8.","cvssScore":4.8,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","cwes":["CWE-1286"],"vendors":[],"products":[],"references":[{"url":"https://github.com/rack/rack/commit/4380381a56dc52556a436d6d794c8e18dc8b0565","tags":[]},{"url":"https://github.com/rack/rack/commit/49386f460286b7346c7003b69a839de782cc8a39","tags":[]},{"url":"https://github.com/rack/rack/releases/tag/v3.1.23","tags":[]},{"url":"https://github.com/rack/rack/releases/tag/v3.2.8","tags":[]},{"url":"https://github.com/rack/rack/security/advisories/GHSA-2j8w-xcrc-x985","tags":[]}],"exploitRefs":[{"url":"https://github.com/rack/rack/commit/4380381a56dc52556a436d6d794c8e18dc8b0565","tags":[]},{"url":"https://github.com/rack/rack/commit/49386f460286b7346c7003b69a839de782cc8a39","tags":[]},{"url":"https://github.com/rack/rack/releases/tag/v3.1.23","tags":[]},{"url":"https://github.com/rack/rack/releases/tag/v3.2.8","tags":[]},{"url":"https://github.com/rack/rack/security/advisories/GHSA-2j8w-xcrc-x985","tags":[]}],"hasPoc":true,"ai":null}