{"id":"CVE-2021-41267","details":"Symfony/Http-Kernel is the HTTP kernel component for Symfony, a PHP framework for web and console applications and a set of reusable PHP components. Headers that are not part of the \"trusted_headers\" allowed list are ignored and protect users from \"Cache poisoning\" attacks. In Symfony 5.2, maintainers added support for the `X-Forwarded-Prefix` headers, but this header was accessible in SubRequest, even if it was not part of the \"trusted_headers\" allowed list. An attacker could leverage this opportunity to forge requests containing a `X-Forwarded-Prefix` header, leading to a web cache poisoning issue. Versions 5.3.12 and later have a patch to ensure that the `X-Forwarded-Prefix` header is not forwarded to subrequests when it is not trusted.","aliases":["BIT-symfony-2021-41267","GHSA-q3j3-w37x-hq2q"],"modified":"2026-10-24T10:50:42.852849150Z","published":"2021-11-24T19:15:07.737Z","database_specific":{"unresolved_ranges":[{"vendor_product":"sensiolabs:symfony","cpes":["cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*"],"extracted_events":[{"source":"CPE_RANGE","range":[{"introduced":"5.2.0"},{"fixed":"5.3.12"}]}]}]},"references":[{"type":"ADVISORY","url":"https://github.com/symfony/symfony/releases/tag/v5.3.12"},{"type":"FIX","url":"https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487"},{"type":"FIX","url":"https://github.com/symfony/symfony/pull/44243"},{"type":"FIX","url":"https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/symfony/symfony","events":[{"introduced":"8b51547061b29081803eb9fdf9b02cf80a1e1a74"},{"fixed":"256c34a45b79fdc6276a8c941a1656713ee1ffec"},{"fixed":"95dcf51682029e89450aee86267e3d553aa7c487"}],"database_specific":{"extracted_events":[{"range":[{"introduced":"5.2.0"},{"fixed":"5.3.12"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*"},{"source":"REFERENCES_COMMIT","range":[{"fixed":"95dcf51682029e89450aee86267e3d553aa7c487"}]},{"source":"REFERENCES_TAG","original_tag":"v5.3.12","range":[{"fixed":"256c34a45b79fdc6276a8c941a1656713ee1ffec"}]}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-41267.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"}]}