oss-sec mailing list archives

CVE request: XXE in perl Image::Info and XML::Twig


From: Doran Moppert <dmoppert () redhat com>
Date: Wed, 2 Nov 2016 15:37:58 +1030

Starting with this bug in XML::LibXML:

XML-LibXML: External entities are parsed by default

https://rt.cpan.org/Public/Bug/Display.html?id=118032
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=838097
https://bugzilla.redhat.com/show_bug.cgi?id=1377996

.. which is an insecure default setting, probably not worthy of a CVE in
itself.


I did a brief audit of other CPAN modules in Fedora that may suffer from
XXE, which uncovered these two:

XML-Twig: expand_external_ents fails to work as documented

https://rt.cpan.org/Public/Bug/Display.html?id=118097
https://bugzilla.redhat.com/show_bug.cgi?id=1379553

This option (which defaults to 0) is supposed to control XXE parsing
documents with XML::Twig, but it has no effect and XXE always takes
place.

No fix is available yet, and my perl isn't up to proposing a sensible
patch.

XML::Twig 1.49 does feature an undocumented option 'NoXxe' which can be
used to prevent entity expansion, but that option isn't present in 1.50
(current development branch) or in earlier versions (up to 1.44) I have
checked.


Image-Info: XXE in SVG files

https://rt.cpan.org/Public/Bug/Display.html?id=118099
https://bugzilla.redhat.com/show_bug.cgi?id=1379556

This was promptly fixed in 1.38_50 / 1.39.


Thanks,
-- 
Doran Moppert
Red Hat Product Security

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