An expat security update has been released for Debian GNU/Linux 11 to address a heap use-after-free vulnerability.

DSA 5266-1: expat security update

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Debian Security Advisory DSA-5266-1 security@debian.org
  https://www.debian.org/security/ Salvatore Bonaccorso
October 30, 2022   https://www.debian.org/security/faq
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Package : expat
CVE ID : CVE-2022-43680
Debian Bug : 1022743

A heap use-after-free vulnerability after overeager destruction of a
shared DTD in the XML_ExternalEntityParserCreate function in Expat, an
XML parsing C library, may result in denial of service or potentially
the execution of arbitrary code.

For the stable distribution (bullseye), this problem has been fixed in
version 2.2.10-2+deb11u5.

We recommend that you upgrade your expat packages.

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

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/