Ubuntu Update for Linux kernel vulnerabilities USN-948-1
Please Install the Updated Packages.
It was discovered that GnuTLS did not always properly verify the hash algorithm of X.509 certificates. If an application linked against GnuTLS processed a crafted certificate, an attacker could make GnuTLS dereference a NULL pointer and cause a DoS via application crash.
gnutls12 vulnerability on Ubuntu 6.06 LTS