Ubuntu Security Notice 929-2 – USN-929-1 fixed vulnerabilities in irssi. The upstream changes introduced a regression when using irssi with SSL and an IRC proxy. This update fixes the problem. It was discovered that irssi did not perform certificate host validation when using SSL connections. An attacker could exploit this to perform a man in the middle attack to view sensitive information or alter encrypted communications. Aurelien Delaitre discovered that irssi could be made to dereference a NULL pointer when a user left the channel. A remote attacker could cause a denial of service via application crash. This update also adds SSLv3 and TLSv1 support, while disabling the old, insecure SSLv2 protocol.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/88721/USN-929-2.txt
Source: https://packetstormsecurity.com/files/88721/Ubuntu-Security-Notice-929-2.html