Vulnerability · Published Nov 24, 2021 · Assigned by GitHub_M
CVE-2021-41267Webcache Poisoning in Symfony
Medium 6.5
In plain English
A medium-severity security flaw in symfony from symfony. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 70% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 "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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Packagist | symfony/http-kernel | 5.3.12 | GHSA-q3j3-w37x-hq2q |
| Packagist | symfony/symfony | 5.3.12 | GHSA-q3j3-w37x-hq2q |
Affected products (as reported)
Weakness: CWE-444 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
References
- https://github.com/symfony/symfony/pull/44243 x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v5.3.12 x_refsource_MISC
- https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q x_refsource_CONFIRM
- https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487 x_refsource_MISC