URL Validation Bypass Vulnerability in PHP Versions 7.3.x, 7.4.x, and 8.0.x

CVE-2021-21705 · MEDIUM Severity

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

In PHP versions 7.3.x below 7.3.29, 7.4.x below 7.4.21 and 8.0.x below 8.0.8, when using URL validation functionality via filter_var() function with FILTER_VALIDATE_URL parameter, an URL with invalid password field can be accepted as valid. This can lead to the code incorrectly parsing the URL and potentially leading to other security implications - like contacting a wrong server or making a wrong access decision.

Learn more about our Cis Benchmark Audit For Server Software.