libxkbcommon: NULL pointer dereference in LookupModMask resulting in a crash

Unchecked NULL pointer usage in LookupModMask in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local attackers to crash NULL pointer dereference the xkbcommon parser by supplying a crafted keymap file with invalid virtual modifiers...

Null pointer dereference

Unchecked NULL pointer usage in LookupModMask in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local attackers to crash NULL pointer dereference the xkbcommon parser by supplying a crafted keymap file with invalid virtual modifiers...