Debian DSA-4000-1 Moderate: Impact of X.Org X Server DoS Vulnerability

Several vulnerabilities have been discovered in the X.Org X server. An
attacker who's able to connect to an X server could cause a denial of
service or potentially the execution of arbitrary code.

For the oldstable distribution (jessie), these problems have been fixed
in version 2:1.16.4-1+deb8u2.

For the stable distribution (stretch), these problems have been fixed in
version 2:1.19.2-1+deb9u2.

We recommend that you upgrade your xorg-server packages.

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/