CVE-2021-41267

MEDIUM6.5EPSS 0.46%

Webcache Poisoning in symfony/http-kernel

發布日:2021/11/24修改日:2026/3/13

描述

Description ----------- When a Symfony application is running behind a proxy or a load-balancer, you can tell Symfony to look for the `X-Forwarded-*` HTTP headers. HTTP headers that are not part of the "trusted_headers" allowed list are ignored and protect you from "Cache poisoning" attacks. In Symfony 5.2, we've added support for the `X-Forwarded-Prefix` header, but this header was accessible in sub-requests, 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` HTTP header, leading to a web cache poisoning issue. Resolution ---------- Symfony now ensures that the `X-Forwarded-Prefix` HTTP header is not forwarded to sub-requests when it is not trusted. The patch for this issue is available [here](https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487) for branch 5.3. Credits ------- We would like to thank Soner Sayakci for reporting the issue and Jérémy Derussé for fixing the issue.

受影響套件(3)

CVSS 分數

來源版本嚴重程度向量
osvCVSS 3.1MEDIUM6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

參考連結(8)