Ubuntu Security Notice 970-1 – It was discovered that GPGSM in GnuPG2 did not correctly handle certificates with a large number of Subject Alternate Names. If a user or automated system were tricked into processing a specially crafted certificate, an attacker could cause a denial of service or execute arbitrary code with privileges of the user invoking the program.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/92710/USN-970-1.txt
Source: https://packetstormsecurity.com/files/92710/Ubuntu-Security-Notice-970-1.html