Input validation error in PHP - CVE-2009-4418
Published: October 30, 2018 / Updated: June 8, 2025
Vulnerability identifier: #VU110313
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:U/U:Green
CVE-ID: CVE-2009-4418
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 non-authenticated attacker to perform service disruption.
The unserialize function in PHP 5.3.0 and earlier allows context-dependent attackers to cause a denial of service (resource consumption) via a deeply nested serialized variable, as demonstrated by a string beginning with a:1: followed by many {a:1: sequences.
How to mitigate CVE-2009-4418
Install update from vendor's website.