Three vulnerabilities have been discovered in the X Font Server possibly allowing local attackers to gain elevated privileges.
|Package||x11-apps/xfs on all architectures|
|Affected versions||< 1.0.5|
|Unaffected versions||>= 1.0.5|
The X.Org X11 X Font Server provides a standard mechanism for an X server to communicate with a font renderer.
iDefense reported that the xfs init script does not correctly handle a race condition when setting permissions of a temporary file (CVE-2007-3103). Sean Larsson discovered an integer overflow vulnerability in the build_range() function possibly leading to a heap-based buffer overflow when handling "QueryXBitmaps" and "QueryXExtents" protocol requests (CVE-2007-4568). Sean Larsson also discovered an error in the swap_char2b() function possibly leading to a heap corruption when handling the same protocol requests (CVE-2007-4990).
The first issue would allow a local attacker to change permissions of arbitrary files to be world-writable by performing a symlink attack. The second and third issues would allow a local attacker to execute arbitrary code with privileges of the user running the X Font Server, usually xfs.
There is no known workaround at this time.
All X Font Server users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=x11-apps/xfs-1.0.5"