Cisco Security Advisory – The H.323 implementation in Cisco IOS Software contains two vulnerabilities that may be exploited remotely to cause a denial of service (DoS) condition on a device that is running a vulnerable version of Cisco IOS Software. Cisco has released free software updates that address these vulnerabilities. There are no workarounds to mitigate these vulnerabilities other than disabling H.323 on the vulnerable device if H.323 is not required.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/87600/cisco-sa-20100324-h323.txt
Source: https://packetstormsecurity.com/files/87600/Cisco-Security-Advisory-20100324-h323.html