The Mu Dynamics Research team has found several vulnerabilities stemming from unsafe use of the sscanf C standard library function. Asterisk versions 1.6.1 through 1.6.1.2 are affected.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/80293/MU-200908-01.txt
Source: https://packetstormsecurity.com/files/80293/MU-Security-Advisory-2009-08.01.html