A libxml2 security update has been released for Debian GNU/Linux 9 LTS to address a security issue.

DLA 2669-1: libxml2 security update

- -------------------------------------------------------------------------
Debian LTS Advisory DLA-2669-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Thorsten Alteholz
May 30, 2021   https://wiki.debian.org/LTS
- -------------------------------------------------------------------------

Package : libxml2
Version : 2.9.4+dfsg1-2.2+deb9u5
CVE ID : CVE-2021-3541

An issue has been found in libxml2, the GNOME XML library.
This issue is called "Parameter Laughs"-attack and is related to parameter
entities expansion.
It is similar to the "Billion Laughs"-attacks found earlier in libexpat.
More information can be found at [1]

[1]   https://blog.hartwork.org/posts/cve-2021-3541-parameter-laughs-fixed-in-libxml2-2-9-11/

For Debian 9 stretch, this problem has been fixed in version
2.9.4+dfsg1-2.2+deb9u5.

We recommend that you upgrade your libxml2 packages.

For the detailed security status of libxml2 please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/libxml2

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