An issue was discovered in Http Foundation in Symfony 2.7.0 through 2.7.48, 2.8.0 through 2.8.43, 3.3.0 through 3.3.17, 3.4.0 through 3.4.13, 4.0.0 through 4.0.13, and 4.1.0 through 4.1.2. It arises from support for a (legacy) IIS header that lets users override the path in the request URL via the X-Original-URL or X-Rewrite-URL HTTP request header. These headers are designed for IIS support, but it's not verified that the server is in fact running IIS, which means anybody who can send these requests to an application can trigger this. This affects \Symfony\Component\HttpFoundation\Request::prepareRequestUri() where X-Original-URL and X_REWRITE_URL are both used. The fix drops support for these methods so that they cannot be used as attack vectors such as web cache poisoning.
https://www.drupal.org/SA-CORE-2018-005
https://symfony.com/blog/cve-2018-14773-remove-support-for-legacy-and-risky-http-headers
https://github.com/symfony/symfony/commit/e447e8b92148ddb3d1956b96638600ec95e08f6b
http://www.securitytracker.com/id/1041405
http://www.securityfocus.com/bid/104943
https://lists.debian.org/debian-lts-announce/2019/03/msg00009.html
Source: MITRE
Published: 2018-08-03
Updated: 2021-09-29
Type: NVD-CWE-noinfo
Base Score: 4
Vector: AV:N/AC:L/Au:S/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 8
Severity: MEDIUM
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Impact Score: 3.6
Exploitability Score: 2.8
Severity: MEDIUM