Details for this vulnerability have not been published by NIST at this point. Descriptions from software vendor advisories for this issue are provided below.
USN-3898-1 fixed a vulnerability in NSS. This update provides the corresponding update for Ubuntu 12.04 ESM.
Original advisory details:
Hanno BÃ¶ck and Damian Poddebniak discovered that NSS incorrectly handled certain CMS functions. A remote attacker could possibly use this issue to cause NSS to crash, resulting in a denial of service.