CVE-2018-14773

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 57.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-08-03 · updated 2026-06-17

Description

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.

Affected products

Debian Linux: 8.0, 9.0
Drupal: from 8.0.0 before 8.5.6 — fixed in 8.5.6
symfony: from 2.7.0 (excl.) through 2.7.48; from 2.8.0 through 2.8.43; from 3.3.0 through 3.3.17; from 3.4.0 through 3.4.13; from 4.0.0 through 4.0.13; from 4.1.0 through 4.1.2

How to fix

Upgrade to a fixed version: Drupal 8.5.6. Check the vendor advisory for mitigations.

References

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