CVE-2015-6834: PHP

Critical severity, CVSS 9.8. EPSS: 46.8% chance of exploitation in the next 30 days.

Multiple use-after-free vulnerabilities in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 allow remote attackers to execute arbitrary code via vectors related to (1) the Serializable interface, (2) the SplObjectStorage class, and (3) the SplDoublyLinkedList class, which are mishandled during unserialization.

Affected products

• PHP PHP: up to and including 5.4.44; version 5.5.0 only; version 5.5.1 only; version 5.5.2 only; version 5.5.3 only; version 5.5.4 only; …

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