[v2.1] Vulnerability in asterisk < 1.8.10.1 may allow remote denial of service
http://downloads.asterisk.org/pub/security/AST-2012-002.pdf
Solution:
- Upgrade to version 1.8.10.1
(from redmine: issue id 1060, created on 2012-03-22, closed on 2012-05-17)