A libxslt security update has been released for Debian GNU/Linux 11 to address a use-after-free flaw.

DSA 5216-1: libxslt security update

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Debian Security Advisory DSA-5216-1 security@debian.org
  https://www.debian.org/security/ Salvatore Bonaccorso
August 24, 2022   https://www.debian.org/security/faq
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Package : libxslt
CVE ID : CVE-2021-30560

Nick Wellnhofer discovered that the xsltApplyTemplates function in
libxslt, an XSLT processing runtime library, is prone to a
use-after-free flaw, resulting in a denial of service, or potentially
the execution of arbitrary code if a specially crafted file is
processed.

For the stable distribution (bullseye), this problem has been fixed in
version 1.1.34-4+deb11u1.

We recommend that you upgrade your libxslt packages.

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

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/