Updated XFree86 packages that fix several security flaws in libXpm, as well as other bugs, are now available for CentOS Linux 3.
XFree86 is an open source implementation of the X Window System. It provides the basic low level functionality which full fledged graphical user interfaces (GUIs) such as GNOME and KDE are designed upon. During a source code audit, Chris Evans discovered several stack overflow flaws and an integer overflow flaw in the X.Org libXpm library used to decode XPM (X PixMap) images. An attacker could create a carefully crafted XPM file which would cause an application to crash or potentially execute arbitrary code if opened by a victim. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the names CAN-2004-0687, CAN-2004-0688, and CAN-2004-0692 to these issues. A flaw was found in the X Display Manager (XDM). XDM is shipped with Red Hat Enterprise Linux, but is not used by default. XDM opened a chooserFd TCP socket even if the DisplayManager.requestPort parameter was set to 0. This allowed authorized users to access a machine remotely via X, even if the administrator had configured XDM to refuse such connections. Although XFree86 4.3.0 was not vulnerable to this issue, CentOS Linux 3 contained a backported patch which introduced this flaw. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2004-0419 to this issue. Users are advised to upgrade to these erratum packages, which contain backported security patches to correct these and a number of other issues.