Under certain circumstances, an attacker might be able to crash GnuTLS.
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.
3 June 2010
A security issue affects these releases of Ubuntu and its derivatives:
Under certain circumstances, an attacker might be able to crash GnuTLS.
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.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.