Bug 1927062 (CVE-2021-26937) - CVE-2021-26937 screen: crash when processing combining chars
Summary: CVE-2021-26937 screen: crash when processing combining chars
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-26937
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
: 1926949 (view as bug list)
Depends On: 1927063 1927064 1927065 1927066 2048282
Blocks: 1927067
TreeView+ depends on / blocked
 
Reported: 2021-02-10 00:33 UTC by Doran Moppert
Modified: 2024-06-14 00:13 UTC (History)
10 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2021-03-08 13:01:52 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:0742 0 None None None 2021-03-08 10:30:07 UTC
Red Hat Product Errata RHSA-2022:1074 0 None None None 2022-03-28 10:30:58 UTC

Description Doran Moppert 2021-02-10 00:33:43 UTC 
A crash was reported in gnu screen when processing a specially crafted sequence of combining characters.  The cause is an out of bounds write, which may be exploitable to cause arbitrary code execution.

https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.html
https://www.openwall.com/lists/oss-security/2021/02/09/3

Upstream bug:

https://savannah.gnu.org/bugs/?60030
Comment 1 Doran Moppert 2021-02-10 00:37:44 UTC 
Created gnome-screensaver tracking bugs for this issue:

Affects: fedora-all [bug 1927066]
Comment 3 Pedro Sampaio 2021-02-10 12:23:58 UTC 
*** Bug 1926949 has been marked as a duplicate of this bug. ***
Comment 4 Doran Moppert 2021-02-11 01:18:16 UTC 
Mitigation:

This flaw is in utf8 processing; if your screen configuration does not enable utf8 (through configuration such as "defencoding utf-8" in .screenrc), you are not vulnerable.
Comment 9 errata-xmlrpc 2021-03-08 10:30:06 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2021:0742 https://access.redhat.com/errata/RHSA-2021:0742
Comment 10 Product Security DevOps Team 2021-03-08 13:01:52 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-26937
Comment 12 errata-xmlrpc 2022-03-28 10:30:55 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7.7 Advanced Update Support
  Red Hat Enterprise Linux 7.7 Update Services for SAP Solutions
  Red Hat Enterprise Linux 7.7 Telco Extended Update Support

Via RHSA-2022:1074 https://access.redhat.com/errata/RHSA-2022:1074
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