Bug 1893339 (CVE-2020-27347)

Summary:	CVE-2020-27347 tmux: stack buffer overflow in input_csi_dispatch_sgr_colon
Product:	[Other] Security Response	Reporter:	Todd Cullum <tcullum>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	dcantrell, rosset.filipe, security-response-team, strobert, sven
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	tmux 3.1c	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-11-03 20:21:15 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1894205, 1910707
Bug Blocks:	1893153

Description Todd Cullum 2020-10-30 19:03:45 UTC

An attacker can crash or execute arbitrary code inside tmux server process by writing a special escape sequence to the pane's pseudo tty. Code execution is proved practical only if tmux address space isn't fully randomized. So ASLR with PIE will mitigiate this issue but more complex exploits may be theoretically created.

Reference:
https://raw.githubusercontent.com/tmux/tmux/3.1c/CHANGES

Upstream patch:
https://github.com/tmux/tmux/commit/a868bacb46e3c900530bed47a1c6f85b0fbe701c

Comment 1 Todd Cullum 2020-11-03 17:59:35 UTC

Acknowledgments:

Name: Sergey Nizovtsev

Comment 2 Todd Cullum 2020-11-03 18:00:48 UTC

Created tmux tracking bugs for this issue:

Affects: fedora-all [bug 1894205]

Comment 3 Todd Cullum 2020-11-03 18:05:01 UTC

Statement:

tmux as shipped with Red Hat Enterprise Linux of any version is not affected because the vulnerable code exists in newer versions of tmux than those shipped.

Comment 4 Todd Cullum 2020-11-03 18:46:51 UTC

The affected version for this flaw is tmux-2.9 and greater.

Comment 5 Product Security DevOps Team 2020-11-03 20:21:15 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-2020-27347