A libxml2 security update has been released for Fedora 33.

SECURITY: Fedora 33 Update: libxml2-2.9.12-4.fc33

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Fedora Update Notification
FEDORA-2021-b950000d2b
2021-06-14 01:22:33.637998
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Name : libxml2
Product : Fedora 33
Version : 2.9.12
Release : 4.fc33
URL :   http://xmlsoft.org/
Summary : Library providing XML and HTML support
Description :
This library allows to manipulate XML files. It includes support
to read, modify and write XML and HTML files. There is DTDs support
this includes parsing and validation even with complex DtDs, either
at parse time or later once the document has been modified. The output
can be a simple SAX stream or and in-memory DOM like representations.
In this case one can use the built-in XPath and XPointer implementation
to select sub nodes or ranges. A flexible Input/Output mechanism is
available, with existing HTTP and FTP modules and combined to an
URI library.

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Update Information:

Update to 2.9.12 * Fix CVE-2021-3516, CVE-2021-3517, CVE-2021-3518,
CVE-2021-3537, CVE-2021-3541 * Verify sources with GPG signature
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ChangeLog:

* Sat May 29 2021 David King - 2.9.12-4
- Fix xmlNodeDumpOutputInternal regression (#1965662)
* Tue May 25 2021 David King - 2.9.12-3
- Fix multiarch conflict in devel subpackage
* Wed May 19 2021 David King - 2.9.12-2
- Fix python-lxml regression with 2.9.12
* Thu May 13 2021 David King - 2.9.12-1
- Update to 2.9.12 (#1960153)
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References:

[ 1 ] Bug #1954227 - CVE-2021-3516 libxml2: use-after-free in xmlEncodeEntitiesInternal() in entities.c [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1954227
[ 2 ] Bug #1954234 - CVE-2021-3517 libxml2: heap-based buffer overflow in xmlEncodeEntitiesInternal() in entities.c [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1954234
[ 3 ] Bug #1954243 - CVE-2021-3518 libxml2: use-after-free in xmlXIncludeDoProcess() in xinclude.c [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1954243
[ 4 ] Bug #1956524 - CVE-2021-3537 libxml2: NULL pointer dereference in valid.c in xmlValidBuildAContentModel [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1956524
[ 5 ] Bug #1960153 - CVE-2021-3541 libxml2: Exponential entity expansion attack bypasses all existing protection mechanisms [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1960153
[ 6 ] Bug #1965662 - please backport regression fix 13ad8736d
  https://bugzilla.redhat.com/show_bug.cgi?id=1965662
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This update can be installed with the "dnf" update program. Use
su -c 'dnf upgrade --advisory FEDORA-2021-b950000d2b' at the command
line. For more information, refer to the dnf documentation available at
  http://dnf.readthedocs.io/en/latest/command_ref.html#upgrade-command-label

All packages are signed with the Fedora Project GPG key. More details on the
GPG keys used by the Fedora Project can be found at
  https://fedoraproject.org/keys