CVE-2021-41267 Information

Description

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 rusted_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 rusted_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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Reference

https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q https://github.com/symfony/symfony/releases/tag/v5.3.12 https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487 https://github.com/symfony/symfony/pull/44243

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

6.5