Race condition in the Xsession script, as used by X Display Manager (xdm) in NetBSD before 20060212, X.Org before 20060225, and Solaris 8 through 10 before 20061006, causes a user's Xsession errors file to have weak permissions before a chmod is performed, which allows local users to read Xsession errors files of other users.

The Xsession script, as used by X Display Manager (xdm) in NetBSD before 20060212, X.Org before 20060317, and Solaris 8 through 10 before 20061006, allows local users to overwrite arbitrary files, or read another user's Xsession errors file, via a symlink attack on a /tmp/xses-$USER file.