CVE-2016-6296: PHP

Critical severity, CVSS 9.8. EPSS: 6.3% chance of exploitation in the next 30 days.

Integer signedness error in the simplestring_addn function in simplestring.c in xmlrpc-epi through 0.54.2, as used in PHP before 5.5.38, 5.6.x before 5.6.24, and 7.x before 7.0.9, allows remote attackers to cause a denial of service (heap-based buffer overflow) or possibly have unspecified other impact via a long first argument to the PHP xmlrpc_encode_request function.

Affected products

• PHP PHP: up to and including 5.5.37; 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; …

Published 2016-07-25. Last modified 2026-06-17.