CVE-2013-6420: Apple Mac OS X

High severity, CVSS 7.5. EPSS: 35.6% chance of exploitation in the next 30 days.

The asn1_time_to_time_t function in ext/openssl/openssl.c in PHP before 5.3.28, 5.4.x before 5.4.23, and 5.5.x before 5.5.7 does not properly parse (1) notBefore and (2) notAfter timestamps in X.509 certificates, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted certificate that is not properly handled by the openssl_x509_parse function.

Affected products

• Apple Mac OS X: up to and including 10.9.1
• Opensuse Opensuse: version 11.4 only; version 12.2 only; version 12.3 only; version 13.1 only
• PHP PHP: version 5.4.0 only; version 5.4.1 only; version 5.4.2 only; version 5.4.3 only; version 5.4.4 only; version 5.4.5 only; …

Published 2013-12-17. Last modified 2026-06-17.