Debian LTS: DLA-2312-1: libx11 security update
Summary
For Debian 9 stretch, this problem has been fixed in version
2:1.6.4-3+deb9u2.
We recommend that you upgrade your libx11 packages.
For the detailed security status of libx11 please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/libx11
Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS