Input validation error in PHP - CVE-2021-21707
Published: November 23, 2021 / Updated: October 27, 2023
Vulnerability identifier: #VU58331
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2021-21707
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: PHP Group
Affected software:
PHP
PHP
Detailed vulnerability description
The vulnerability allows a remote attacker to inject arbitrary XML code.
The vulnerability exists due to insufficient validation of user-supplied input within the simplexml_load_file() PHP function when processing NULL byte character (e.g. %00). A remote attacker can pass specially crafted URL to the application and bypass implemented security restrictions.
How to mitigate CVE-2021-21707
Install updates from vendor's website.