The Linux 2.4 and 2.6 kernel series suffer from a flaw where an unprivileged local user may send arbitrary signals to a child process despite security restrictions.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/58557/linux-signal.txt
Source: https://packetstormsecurity.com/files/58557/linux-signal.txt.html