The libvorbis packages contain runtime libraries for use in programs that support Ogg Vorbis. Ogg Vorbis is a fully open, non-proprietary, patent-and royalty-free, general-purpose compressed audio format.
An insufficient input validation flaw was found in the way libvorbis processes the codec file headers (static mode headers and encoding books) of the Ogg Vorbis audio file format (Ogg). A remote attacker could provide a specially-crafted Ogg file that would cause a denial of service (memory corruption and application crash) or, potentially, execute arbitrary code with the privileges of an application using the libvorbis library when opened by a victim. (CVE-2009-2663)
Users of libvorbis should upgrade to these updated packages, which contain a backported patch to correct this issue. The desktop must be restarted (log out, then log back in) for this update to take effect.