#VU1001 Use-after-free error in PHP - CVE-2015-6835
Published: October 14, 2016 / Updated: April 7, 2020
Vulnerability identifier: #VU1001
Vulnerability risk: High
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber
CVE-ID: CVE-2015-6835
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vulnerable software:
PHP
PHP
Software vendor:
PHP Group
PHP Group
Description
The vulnerability alows a remote unauthenticated user to execute arbitrary code or cause DoS conditions on the target system.
The weakness exists due to incorrect processing of multiple php_var_unserialize calls while deserializing data with the session deserializer. By sending a specially crafted serialized string, attackers can trigger a use-after-free that can be used to execute arbitrary code or cause a service crash.
Successful exploitation of the vulnerability results in arbitrary code execution or denial of service on the vulnerable system.
The weakness exists due to incorrect processing of multiple php_var_unserialize calls while deserializing data with the session deserializer. By sending a specially crafted serialized string, attackers can trigger a use-after-free that can be used to execute arbitrary code or cause a service crash.
Successful exploitation of the vulnerability results in arbitrary code execution or denial of service on the vulnerable system.
Remediation
Update to version 5.5.38, 5.6.27 or 7.0.12.