Improper input validation in PHP

1) Input validation error

EUVDB-ID: #VU58331

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-21707

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

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.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

PHP: 7.3 - 8.0.12

External links

http://www.php.net/ChangeLog-8.php#8.0.13
http://www.php.net/ChangeLog-7.php#7.4.26
http://www.php.net/ChangeLog-7.php#7.3.33
http://bugs.php.net/bug.php?id=79971

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.