Extcompose, a function of the metamail package, fails to properly verify a file exists prior to writing to it, and will accept symbolic links, leaving it open to being an attack vector.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/32855/extcompose.txt
Source: https://packetstormsecurity.com/files/32855/extcompose.txt.html