A format string flaw was found in the way xorg-x11-server, a X.Org X11 X server, performed log message writes for certain forms of the log message to be written. If a local attacker assigned a specially-crafted name to a input device and was able to trick the system administrator in order to the local Xorg server instance to use this device, it would lead to Xorg service instance abort.
Upstream patch series:
Possible way to reproduce (from ):
1. Name a Bluetooth keyboard "%n%n%n%n%n%n%n%n"
2. Pair it with a computer running X and try to use it
3. X is not happy when trying to do the following in xf86-input-evdev:
xf86IDrvMsg(pInfo, X_CONFIG, "Device: "%s"\n", device);
because LogVHdrMessageVerb() has put the %n from the device name
into a format string.
This issue affects the version of the xorg-x11-server package, as shipped with Red Hat Enterprise Linux 5 and 6.
This issue affects the version of the xorg-x11-server package, as shipped with Fedora release of 15 and 16. Please schedule an update.
Created xorg-x11-server tracking bugs for this issue
Affects: fedora-all [bug 814128]
The version of xorg-x11-server in Red Hat Enterprise Linux 5 and 6, is protected by format string protections since its compiled with FORTIFY_SOURCE enabled. Hence the maximum impact of this flaw is limited to crash only.
Further, to exploit this issue, the attacker would need physical access to the system.
Red Hat does not consider crash of end user application such as xorg-x11-server caused by local user actions to be a security flaw.