CVE-2021-41267

published 2021-11-24

CVE-2021-41267: 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…

Priority P4 31 medium 6.5 CVSS 3.1

AV N AC L PR N UI R S U C N I H A N

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.

Affected

5 ranges

Vendor	Product	Version range	Fixed in
debian	symfony	—	—
sensiolabs	symfony	>= 5.2.0 < 5.3.12	5.3.12
symfony	http-kernel	>= 5.2.0 < 5.3.12	5.3.12
symfony	symfony	—	—
symfony	symfony	>= 5.2.0 < 5.3.12	5.3.12

CVSS provenance

nvd v3.1 6.5 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

nvd v2.0 4.3 MEDIUM AV:N/AC:M/Au:N/C:N/I:P/A:N

osv 6.5 MEDIUM

vendor_debian 6.5 LOW

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.

CWE-444