python-lxml is vulnerable to CVE-2021-28957

DoneSubmitted by Léo Le Bouter.
Details
4 participants
  • Leo Famulari
  • Léo Le Bouter
  • Maxim Cournoyer
  • Mark H Weaver
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unassigned
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Léo Le Bouter wrote on 22 Mar 2021 15:09
(address . bug-guix@gnu.org)
8e3d68f9e674d1556bf2ba6baff0e72c069a2673.camel@zaclys.net
CVE-2021-28957 21.03.21 06:15
lxml 4.6.2 places the HTML action attribute into defs.link_attrs (in
html/defs.py) for later use in input sanitization, but does not do the
same for the HTML5 formaction attribute.

Upstream fixed it in 4.6.3 (
), so we should probably upgrade to that.

Has lots of dependents so I suppose it needs grafting? Is that useful
and does it work for Python packages?

Léo
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Léo Le Bouter wrote on 22 Mar 2021 15:10
(address . control@debbugs.gnu.org)
0fece03a442059eec9966ab9e1de32d02df89b81.camel@zaclys.net
tags 47319 + security
quit
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Léo Le Bouter wrote on 23 Mar 2021 16:29
(address . 47319@debbugs.gnu.org)
cd5fd0c50f8229e7c8c729d810c373256590739b.camel@zaclys.net
I pushed a9d540cfa87ef3a5de3296188f650fb0d037efbd on core-updates, how
to fix it on master considering the amount of dependents remains to be
agreed on.
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Leo Famulari wrote on 23 Mar 2021 18:55
(name . Léo Le Bouter via Bug reports for GNU Guix)(address . bug-guix@gnu.org)(address . 47319@debbugs.gnu.org)
YFori3lHDKLjAEyE@jasmine.lan
On Mon, Mar 22, 2021 at 03:09:24PM +0100, Léo Le Bouter via Bug reports for GNU Guix wrote:
Toggle quote (5 lines)
> CVE-2021-28957 21.03.21 06:15
> lxml 4.6.2 places the HTML action attribute into defs.link_attrs (in
> html/defs.py) for later use in input sanitization, but does not do the
> same for the HTML5 formaction attribute.

Thanks for the notification.

I checked on some other distros that, like us, try to avoid major
updates of packages with a lot of dependents:


So, both Debian and Red Hat are still shipping the vulnerable packages.
At least, we are in good company. We would monitor the Debian page and
copy their patch, if they decide to fix the bug.

Toggle quote (7 lines)
> Upstream fixed it in 4.6.3 (
> https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d
> ), so we should probably upgrade to that.
>
> Has lots of dependents so I suppose it needs grafting? Is that useful
> and does it work for Python packages?

Grafting Python packages is not something we've done in the past, as far
as I can tell from reading the Git log, although I don't recall know if
it works or not.
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Mark H Weaver wrote on 6 Apr 2021 01:54
87wntg5lsm.fsf@netris.org
Leo Famulari <leo@famulari.name> writes:

Toggle quote (8 lines)
> On Mon, Mar 22, 2021 at 03:09:24PM +0100, Léo Le Bouter via Bug reports for GNU Guix wrote:
>> Has lots of dependents so I suppose it needs grafting? Is that useful
>> and does it work for Python packages?
>
> Grafting Python packages is not something we've done in the past, as far
> as I can tell from reading the Git log, although I don't recall know if
> it works or not.

I see no reason why grafting a python package wouldn't work, although
admittedly my knowledge of Python is weak.

Mark
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Maxim Cournoyer wrote on 23 Mar 03:32 +0100
(name . Léo Le Bouter)(address . lle-bout@zaclys.net)(address . 47319-done@debbugs.gnu.org)
874k3p1jqj.fsf@gmail.com
Hi,

Léo Le Bouter <lle-bout@zaclys.net> writes:

Toggle quote (9 lines)
> CVE-2021-28957 21.03.21 06:15
> lxml 4.6.2 places the HTML action attribute into defs.link_attrs (in
> html/defs.py) for later use in input sanitization, but does not do the
> same for the HTML5 formaction attribute.
>
> Upstream fixed it in 4.6.3 (
> https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d
> ), so we should probably upgrade to that.

This is the current version in Guix.

Closing; thanks!

Maxim
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