Cisco Security Advisory – Multiple vulnerabilities exist in the Session Initiation Protocol (SIP) implementation in Cisco IOS that can be exploited remotely to trigger a memory leak or to cause a reload of the IOS device. Cisco has released free software updates that address these vulnerabilities. Fixed Cisco IOS software listed in the Software Versions and Fixes section contains fixes for all vulnerabilities addressed in this advisory.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/70315/cisco-sa-20080924-sip.txt
Source: https://packetstormsecurity.com/files/70315/Cisco-Security-Advisory-20080924-sip.html