A security issue affects the following Ubuntu releases:
Ubuntu 5.04
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 5.04: libksba8 0.9.9-2ubuntu0.5.04
After a standard system upgrade you need to restart your session to effect the necessary changes.
Details follow:
A parsing failure was discovered in the handling of X.509 certificates that contained extra trailing data. Malformed or malicious certificates could cause services using libksba to crash, potentially creating a denial of service.