Bug 1927559 (CVE-2021-27135) - CVE-2021-27135 xterm: crash when processing combining characters
Summary: CVE-2021-27135 xterm: crash when processing combining characters
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-27135
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:
Depends On: 1927564 1927565 1927566 1927567 1927568 1927569 1927570
Blocks: 1927561
TreeView+ depends on / blocked
 
Reported: 2021-02-11 01:13 UTC by Doran Moppert
Modified: 2022-04-17 21:08 UTC (History)
1 user (show)

Fixed In Version: xterm 366
Clone Of:
Environment:
Last Closed: 2021-02-18 19:02:54 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:0611 0 None None None 2021-02-18 14:54:28 UTC
Red Hat Product Errata RHSA-2021:0617 0 None None None 2021-02-22 11:12:15 UTC
Red Hat Product Errata RHSA-2021:0650 0 None None None 2021-02-24 07:45:27 UTC
Red Hat Product Errata RHSA-2021:0651 0 None None None 2021-02-24 07:54:51 UTC

Description Doran Moppert 2021-02-11 01:13:00 UTC 
A crash was reported in xterm prior to patch #366 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://www.openwall.com/lists/oss-security/2021/02/09/7
https://invisible-island.net/xterm/xterm.log.html
Comment 1 Doran Moppert 2021-02-11 01:24:06 UTC 
Created xterm tracking bugs for this issue:

Affects: fedora-all [bug 1927570]
Comment 4 Doran Moppert 2021-02-11 02:57:29 UTC 
Mitigation:

This vulnerability can be mitigated by disabling UTF-8 support in XTerm configuration.  An entry such as "XTerm.vt100.utf8: false" in Xresources will disable UTF-8.  This can be set as a system default in /etc/X11/Xresources, or per-user in ~/.Xresources.

Note that this setting can still be overridden if xterm is invoked with the "-u8" command line option, so the mitigation may not protect all use cases.
Comment 5 errata-xmlrpc 2021-02-18 14:54:27 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:0611 https://access.redhat.com/errata/RHSA-2021:0611
Comment 6 Product Security DevOps Team 2021-02-18 19:02:54 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-2021-27135
Comment 7 errata-xmlrpc 2021-02-22 11:12:12 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2021:0617 https://access.redhat.com/errata/RHSA-2021:0617
Comment 8 errata-xmlrpc 2021-02-24 07:45:25 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.1 Extended Update Support

Via RHSA-2021:0650 https://access.redhat.com/errata/RHSA-2021:0650
Comment 9 errata-xmlrpc 2021-02-24 07:54:50 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.2 Extended Update Support

Via RHSA-2021:0651 https://access.redhat.com/errata/RHSA-2021:0651
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