Multiple buffer overflows in apcupsd before 3.8.6, and 3.10.x before 3.10.5, may allow attackers to cause a denial of service or execute arbitrary code, related to usage of the vsprintf function.
APC UPS daemon, apcupsd, saves its process ID in a world-writable file, which allows local users to kill an arbitrary process by specifying the target process ID in the apcupsd.pid file.