Debian Security Advisory 1294-1 - Several vulnerabilities have been discovered in the X Window System, which may lead to privilege escalation.
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Gentoo Linux Security Advisory GLSA 200705-10 - The libXfont code is prone to several integer overflows, in functions ProcXCMiscGetXIDList(), bdfReadCharacters() and FontFileInitTable(). TightVNC contains a local copy of this code and is also affected. Versions less than 1.2.9-r4 are affected.
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Mandriva Linux Security Advisory - Local exploitation of a memory corruption vulnerability in the X.Org and XFree86 X server could allow an attacker to execute arbitrary code with privileges of the X server, typically root. iDefense reported two integer overflows in the way X.org handled various font files. A malicious local user could exploit these issues to potentially execute arbitrary code with the privileges of the X.org server.
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Mandriva Linux Security Advisory - Local exploitation of a memory corruption vulnerability in the X.Org and XFree86 X server could allow an attacker to execute arbitrary code with privileges of the X server, typically root. The vulnerability exists in the ProcXCMiscGetXIDList() function in the XC-MISC extension. This request is used to determine what resource IDs are available for use. This function contains two vulnerabilities, both result in memory corruption of either the stack or heap. The ALLOCATE_LOCAL() macro used by this function allocates memory on the stack using alloca() on systems where alloca() is present, or using the heap otherwise. The handler function takes a user provided value, multiplies it, and then passes it to the above macro. This results in both an integer overflow vulnerability, and an alloca() stack pointer shifting vulnerability. Both can be exploited to execute arbitrary code. iDefense reported two integer overflows in the way X.org handled various font files. A malicious local user could exploit these issues to potentially execute arbitrary code with the privileges of the X.org server. TightVNC uses some of the same code base as Xorg, and has the same vulnerable code.
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Mandriva Linux Security Advisory - Local exploitation of a memory corruption vulnerability in the X.Org and XFree86 X server could allow an attacker to execute arbitrary code with privileges of the X server, typically root. The vulnerability exists in the ProcXCMiscGetXIDList() function in the XC-MISC extension. This request is used to determine what resource IDs are available for use. This function contains two vulnerabilities, both result in memory corruption of either the stack or heap. The ALLOCATE_LOCAL() macro used by this function allocates memory on the stack using alloca() on systems where alloca() is present, or using the heap otherwise. The handler function takes a user provided value, multiplies it, and then passes it to the above macro. This results in both an integer overflow vulnerability, and an alloca() stack pointer shifting vulnerability. Both can be exploited to execute arbitrary code. iDefense reported two integer overflows in the way X.org handled various font files. A malicious local user could exploit these issues to potentially execute arbitrary code with the privileges of the X.org server. Multiple integer overflows in the XGetPixel function in ImUtil.c in x.org libx11 before 1.0.3, and XInitImage function in xwd.c for ImageMagick, allow user-assisted remote attackers to cause a denial of service (crash) or information leak via crafted images with large or negative values that trigger a buffer overflow.
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iDefense Security Advisory 04.03.07 - Local exploitation of an integer overflow vulnerability in multiple vendors' implementations of the X Window System font information file parsing component could allow execution of arbitrary commands with elevated privileges. The vulnerability specifically exists in the parsing of the "fonts.dir" font information file. When the element count on the first line of the file specifies it contains more than 1,073,741,824 (2 to the power of 30) elements, a potentially exploitable heap overflow condition occurs. iDefense has confirmed the existence of this vulnerability in X.Org X11R7.1. Older versions are suspected to be vulnerable.
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Ubuntu Security Notice 448-1 - Sean Larsson of iDefense Labs discovered that the MISC-XC extension of Xorg did not correctly verify the size of allocated memory. An authenticated user could send a specially crafted X11 request and execute arbitrary code with root privileges. Greg MacManus of iDefense Labs discovered that the BDF font handling code in Xorg and FreeType did not correctly verify the size of allocated memory. If a user were tricked into using a specially crafted font, a remote attacker could execute arbitrary code with root privileges.
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