Ubuntu Security Notice 2391-1 – Symeon Paraschoudis discovered that PHP incorrectly handled the mkgmtime function. A remote attacker could possibly use this issue to cause PHP to crash, resulting in a denial of service. Symeon Paraschoudis discovered that PHP incorrectly handled unserializing objects. A remote attacker could possibly use this issue to cause PHP to crash, resulting in a denial of service. Otto Ebeling discovered that PHP incorrectly handled the exif_thumbnail function. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. Various other issues were also addressed.