Use-after-free in PHP - CVE-2021-21708
Published: February 18, 2022 / Updated: October 27, 2023
Vulnerability identifier: #VU60707
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2021-21708
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: PHP Group
Affected software:
PHP
PHP
Detailed vulnerability description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a use-after-free error within the "php_filter_float()" function. A remote attacker can pass specially crafted input to the application that uses the affected PHP function, trigger a use-after-free error and crash the php-fpm process.
How to mitigate CVE-2021-21708
Install updates from vendor's website.