CVE-2015-6835: PHP

Critical severity, CVSS 9.8. EPSS: 36.2% chance of exploitation in the next 30 days.

The session deserializer in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 mishandles multiple php_var_unserialize calls, which allow remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via crafted session content.

Affected products

• PHP PHP: version 5.6.0 only; version 5.6.1 only; version 5.6.2 only; version 5.6.3 only; version 5.6.4 only; version 5.6.5 only; …

Published 2016-05-16. Last modified 2026-06-17.