Bug 1646389 (CVE-2018-18020) - CVE-2018-18020 qpdf: recursive calls can lead to a DoS in libqpdf/QPDFWriter.cc
Summary: CVE-2018-18020 qpdf: recursive calls can lead to a DoS in libqpdf/QPDFWriter.cc
Alias: CVE-2018-18020
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Whiteboard: impact=low,public=20181006,reported=2...
Depends On: 1646390 1646391 1646392
Blocks: 1646395
TreeView+ depends on / blocked
Reported: 2018-11-05 14:02 UTC by Laura Pardo
Modified: 2019-06-08 23:42 UTC (History)
3 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Last Closed: 2018-11-28 11:09:42 UTC

Attachments (Terms of Use)

Description Laura Pardo 2018-11-05 14:02:01 UTC
A flaw was found in QPDF 8.2.1, in libqpdf/QPDFWriter.cc, QPDFWriter::unparseObject and QPDFWriter::unparseChild have recursive calls for a long time, which allows remote attackers to cause a denial of service via a crafted PDF file.


Comment 1 Laura Pardo 2018-11-05 14:02:51 UTC
Created qpdf tracking bugs for this issue:

Affects: epel-6 [bug 1646390]
Affects: fedora-all [bug 1646391]

Comment 3 Stefan Cornelius 2018-11-28 11:09:42 UTC
I failed to reproduce this behavior during my testing. However, the real problem here seems to be the use of an arbitrary limit. Finding such limits is always a balancing act.

If you run into this problem in a real world scenario, please comment and we'll investigate and possibly adjust the limit.

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