Apache HTTP Server Vulnerability - CVE-2002-0839
The shared memory scoreboard in the HTTP daemon for Apache 1.3.x before 1.3.27 allows any user running as the Apache UID to send a SIGUSR1 signal to any process as root resulting in a denial of service (process kill) or possibly other behaviors that would not normally be allowed by modifying the parent.pid and parent.last_rtime segments in the scoreboard.