An integer overflow vulnerability leading to a double-free was found in libX11. This flaw allows a local privileged attacker to cause an application compiled with libX11 to crash, or in some cases, result in arbitrary code execution. The highest threat from this flaw is to confidentiality, integrity as well as system availability.
An integer overflow leading to a heap-buffer overflow was found in The X Input Method (XIM) client was implemented in libX11 before version 1.6.10. As per upstream this is security relevant when setuid programs call XIM client functions while running with elevated privileges. No such programs are shipped with Red Hat Enterprise Linux.
An issue was discovered in libX11 through 1.6.5. The function XListExtensions in ListExt.c interprets a variable as signed instead of unsigned, resulting in an out-of-bounds write (of up to 128 bytes), leading to DoS or remote code execution.
An issue was discovered in libX11 through 1.6.5. The function XListExtensions in ListExt.c is vulnerable to an off-by-one error caused by malicious server responses, leading to DoS or possibly unspecified other impact.
An issue was discovered in XListExtensions in ListExt.c in libX11 through 1.6.5. A malicious server can send a reply in which the first string overflows, causing a variable to be set to NULL that will be freed later on, leading to DoS (segmentation fault).
The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
The XGetImage function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving image type and geometry, which triggers out-of-bounds read operations.