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.

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.