libvorbis is the reference implementation of the Xiph.org Ogg Vorbis audio file format. It is used by many applications for playback of Ogg Vorbis files.
David Thiel of iSEC Partners discovered a heap-based buffer overflow in the _01inverse() function in res0.c and a boundary checking error in the vorbis_info_clear() function in info.c (CVE-2007-3106 and CVE-2007-4029). libvorbis is also prone to several Denial of Service vulnerabilities in form of infinite loops and invalid memory access with unknown impact (CVE-2007-4065 and CVE-2007-4066).
A remote attacker could exploit these vulnerabilities by enticing a user to open a specially crafted Ogg Vorbis file or network stream with an application using libvorbis. This might lead to the execution of arbitrary code with privileges of the user playing the file or a Denial of Service by a crash or CPU consumption.
There is no known workaround at this time.
All libvorbis users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=media-libs/libvorbis-1.2.0"