Multiple buffer overflows in X.Org libXfont before 1.4.8 and 1.4.9x before 1.4.99.901 allow remote font servers to execute arbitrary code via a crafted xfs protocol reply to the (1) _fs_recv_conn_setup, (2) fs_read_open_font, (3) fs_read_query_info, (4) fs_read_extent_info, (5) fs_read_glyphs, (6) fs_read_list, or (7) fs_read_list_info function.
Multiple integer overflows in the (1) fs_get_reply, (2) fs_alloc_glyphs, and (3) fs_read_extent_info functions in X.Org libXfont before 1.4.8 and 1.4.9x before 1.4.99.901 allow remote font servers to execute arbitrary code via a crafted xfs reply, which triggers a buffer overflow.
xkeyboard-config before 2.5 in X.Org before 7.6 enables certain XKB debugging functions by default, which allows physically proximate attackers to bypass an X screen lock via keyboard combinations that break the input grab.
Stack-based buffer overflow in the bdfReadCharacters function in bitmap/bdfread.c in X.Org libXfont 1.1 through 1.4.6 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via a long string in a character name in a BDF font file.
X.Org xdm 1.1.10, 1.1.11, and possibly other versions, when performing authentication using certain implementations of the crypt API function that can return NULL, allows remote attackers to cause a denial of service (NULL pointer dereference and crash) by attempting to log into an account whose password field contains invalid characters, as demonstrated using the crypt function from glibc 2.17 and later with (1) the "!" character in the salt portion of a password field or (2) a password that has been encrypted using DES or MD5 in FIPS-140 mode.
Use-after-free vulnerability in the doImageText function in dix/dixfonts.c in the xorg-server module before 1.14.4 in X.Org X11 allows remote authenticated users to cause a denial of service (daemon crash) or possibly execute arbitrary code via a crafted ImageText request that triggers memory-allocation failure.
X.org libXt 1.1.3 and earlier does not check the return value of the XGetWindowProperty function, which allows X servers to trigger use of an uninitialized pointer and memory corruption via vectors related to the (1) ReqCleanup, (2) HandleSelectionEvents, (3) ReqTimedOut, (4) HandleNormal, and (5) HandleSelectionReplies functions.
Buffer overflow in X.org libXv 1.0.7 and earlier allows X servers to cause a denial of service (crash) and possibly execute arbitrary code via crafted length or index values to the XvQueryPortAttributes function.
X.org libFS 1.0.4 and earlier allows X servers to trigger allocation of insufficient memory and a buffer overflow via vectors related to an unexpected sign extension in the FSOpenServer function.
Multiple buffer overflows in X.org libX11 1.5.99.901 (1.6 RC1) and earlier allow X servers to cause a denial of service (crash) and possibly execute arbitrary code via crafted length or index values to the (1) XAllocColorCells, (2) _XkbReadGetDeviceInfoReply, (3) _XkbReadGeomShapes, (4) _XkbReadGetGeometryReply, (5) _XkbReadKeySyms, (6) _XkbReadKeyActions, (7) _XkbReadKeyBehaviors, (8) _XkbReadModifierMap, (9) _XkbReadExplicitComponents, (10) _XkbReadVirtualModMap, (11) _XkbReadGetNamesReply, (12) _XkbReadGetMapReply, (13) _XimXGetReadData, (14) XListFonts, (15) XListExtensions, and (16) XGetFontPath functions.