In the pcfGetProperties function in bitmap/pcfread.c in libXfont through 1.5.2 and 2.x before 2.0.2, a missing boundary check (for PCF files) could be used by local attackers authenticated to an Xserver for a buffer over-read, for information disclosure or a crash of the X server.
www.debian.org/security/2017/dsa-3995
bugzilla.redhat.com/show_bug.cgi?id=1500693
bugzilla.suse.com/show_bug.cgi?id=1049692
cgit.freedesktop.org/xorg/lib/libXfont/commit/?id=672bb944311392e2415b39c0d63b1e1902905bcd
security.gentoo.org/glsa/201711-08
www.x.org/releases/individual/lib/libXfont2-2.0.2.tar.bz2