Bug 1870231 (CVE-2020-16293) - CVE-2020-16293 ghostscript: NULL pointer dereference in compose_group_nonknockout_nonblend_isolated_allmask_common() in base/gxblend.c could result in a DoS
Summary: CVE-2020-16293 ghostscript: NULL pointer dereference in compose_group_nonknoc...
Alias: CVE-2020-16293
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1870233 1872070 1872071
Blocks: 1870273
TreeView+ depends on / blocked
Reported: 2020-08-19 15:13 UTC by Michael Kaplan
Modified: 2021-05-18 20:35 UTC (History)
6 users (show)

Fixed In Version: ghostscript 9.51
Doc Type: If docs needed, set a value
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Clone Of:
Last Closed: 2021-05-18 20:35:25 UTC

Attachments (Terms of Use)

Description Michael Kaplan 2020-08-19 15:13:23 UTC
A null pointer dereference vulnerability in compose_group_nonknockout_nonblend_isolated_allmask_common() in base/gxblend.c of Artifex Software GhostScript v9.50 allows a remote attacker to cause a denial of service via a crafted PDF file. This is fixed in v9.51.



Comment 1 Michael Kaplan 2020-08-19 15:14:46 UTC
Created ghostscript tracking bugs for this issue:

Affects: fedora-all [bug 1870233]

Comment 3 Todd Cullum 2020-08-24 23:49:27 UTC
Flaw summary: 

In /base/gxblend.c routines do_compose_group() and do_compose_group16(), the check if (has_mask || maskbuf) should be if (has_mask && maskbuf). Since it is not, it's possible for compose_group_nonknockout_nonblend_isolated_allmask_common() to be called without a mask, and a dereference of memory pointed to by mask_row_ptr causes a crash. An attacker would need to trigger this by supplying a crafted PDF file to be processed by ghostscript.

Comment 4 Todd Cullum 2020-08-24 23:50:55 UTC

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Comment 6 errata-xmlrpc 2021-05-18 15:37:04 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:1852 https://access.redhat.com/errata/RHSA-2021:1852

Comment 7 Product Security DevOps Team 2021-05-18 20:35:25 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


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