In tmux before version 3.1c the function input_csi_dispatch_sgr_colon() in file input.c contained a stack-based buffer-overflow that can be exploited by terminal output.

The remote CentOS Linux 9 host has a package installed that is affected by a vulnerability as referenced in the tmux-3.2a-4.el9 build changelog.

  - In tmux before version 3.1c the function input_csi_dispatch_sgr_colon() in file input.c contained a stack-     based buffer-overflow that can be exploited by terminal output. (CVE-2020-27347)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

An update of the tmux package has been released.

According to the version of the tmux package installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - In tmux before version 3.1c the function     input_csi_dispatch_sgr_colon() in file input.c     contained a stack-based buffer-overflow that can be     exploited by terminal output.(CVE-2020-27347)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the version of the tmux package installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - The function input_csi_dispatch_sgr_colon() in file     input.c contained a stack-based buffer-overflow that     can be exploited by terminal output.(CVE-2020-27347)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote host is affected by the vulnerability described in GLSA-202011-10 (tmux: Buffer overflow)

    A flaw in tmux&rsquo;s handling of escape characters was discovered which       may allow a buffer overflow.
  Impact :

    A remote attacker could possibly execute arbitrary code with the       privileges of the process, or cause a Denial of Service condition.
  Workaround :

    There is no known workaround at this time.

This update for tmux fixes the following issues :

  - Update to version 3.1c

  - Fix a stack overflow on colon-separated CSI parsing.
    boo#1178263 CVE-2020-27347

  - tmux 3.1b :

  - Fix crash when allow-rename ison and an empty name is     set

  - tmux 3.1a :

  - Do not close stdout prematurely in control mode since it     is needed to print exit messages. Prevents hanging when     detaching with iTerm2

  - includes changes between 3.1-rc1 and 3.1 :

  - Only search the visible part of the history when marking     (highlighting) search terms. This is much faster than     searching the whole history and solves problems with     large histories. The count of matches shown is now the     visible matches rather than all matches

  - Search using regular expressions in copy mode.
    search-forward and search-backward use regular     expressions by default; the incremental versions do not

  - Turn off mouse mode 1003 as well as the rest when     exiting

  - Add selection_active format for when the selection is     present but not moving with the cursor

  - Fix dragging with modifier keys, so binding keys such as     C-MouseDrag1Pane and C-MouseDragEnd1Pane now work

  - Add -a to list-keys to also list keys without notes with
    -N

  - Do not jump to next word end if already on a word end     when selecting a word; fixes select-word with single     character words and vi(1) keys

  - Fix top and bottom pane calculation with pane border     status enabled

  - Update to v3.1-rc

  - Please see the included CHANGES file

  - Fix tmux completion

  - Update to v3.0a

  - A lot of changes since v2.9a, please see the included     CHANGES file.

  - Update to v2.9a

  - Fix bugs in select-pane and the main-horizontal and     main-vertical layouts.

  - Add trailing newline to tmpfiles.d/tmux.conf. On newer     systems (such as Leap 15.1), the lack of a trailing     newline appears to cause the directory to not be     created. This is only evident on setups where /run is an     actual tmpfs (on btrfs-root installs, /run is a btrfs     subvolume and thus /run/tmux is persistent across     reboots).

  - Update to version 2.9

  - Add format variables for the default formats in the     various modes (tree_mode_format and so on) and add a -a     flag to display-message to list variables with values.

  - Add a -v flag to display-message to show verbose     messages as the format is parsed, this allows formats to     be debugged

  - Add support for HPA (\033[`).

  - Add support for origin mode (\033[?6h).

  - No longer clear history on RIS.

  - Extend the #[] style syntax and use that together with     previous format changes to allow the status line to be     entirely configured with a single option.

  - Add E: and T: format modifiers to expand a format twice     (useful to expand the value of an option).

  - The individual -fg, -bg and -attr options have been     removed; they were superseded by -style options in tmux     1.9.

  - Add -b to display-panes like run-shell.

  - Handle UTF-8 in word-separators option.

  - New 'terminal' colour allowing options to use the     terminal default colour rather than inheriting the     default from a parent option.

  - Do not move the cursor in copy mode when the mouse wheel     is used.

  - Use the same working directory rules for jobs as new     windows rather than always starting in the user's home.

  - Allow panes to be one line or column in size.

  - Go to last line when goto-line number is out of range in     copy mode.

  - Yank previously cut text if any with C-y in the command     prompt, only use the buffer if no text has been cut.

  - Add q: format modifier to quote shell special     characters.

  - Add -Z to find-window.

  - Support for windows larger than the client. This adds     two new options, window-size and default-size, and a new     command, resize-window. The force-width and force-height     options and the session_width and session_height formats     have been removed.

  - update to 2.8

  - move bash-completion to right place

  - Make display-panes block the client until a pane is     chosen or it times out.

  - Clear history on RIS like most other terminals do.

  - Add an 'Any' key to run a command if a key is pressed     that is not bound in the current key table.

  - Expand formats in load-buffer and save-buffer.

  - Add a rectangle_toggle format.

  - Add set-hook -R to run a hook immediately.

  - Add pane focus hooks.

  - Allow any punctuation as separator for s/x/y not only /.

  - Improve resizing with the mouse (fix resizing the wrong     pane in some layouts, and allow resizing multiple panes     at the same time).

  - Allow , and ) to be escaped in formats as #, and #).

  - Add KRB5CCNAME to update-environment.

  - Change meaning of -c to display-message so the client is     used if it matches the session given to -t.

  - Fixes to : form of SGR.

  - Add x and X to choose-tree to kill sessions, windows or     panes.

  - Add bash completion for tmux

  - Update to 2.7

  - Remove EVENT_* variables from environment on platforms     where tmux uses them so they do not pass on to panes.

  - Fixed for hooks at server exit.

  - Remove SGR 10 (was equivalent to SGR 0 but no other     terminal seems to do this).

  - Expand formats in window and session names.

  - Add -Z flag to choose-tree, choose-client, choose-buffer     to automatically zoom the pane when the mode is entered     and unzoom when it exits, assuming the pane is not     already zoomed. This is now part of the default key     bindings.

  - Add C-g to exit modes with emacs keys.

  - Add exit-empty option to exit server if no sessions     (default = on)

  - Show if a filter is present in choose modes.

  - Add pipe-pane -I to to connect stdin of the child     process.

  - Performance improvements for reflow.

  - Use RGB terminfo(5) capability to detect RGB colour     terminals (the existing Tc extension remains unchanged).

  - Support for ISO colon-separated SGR sequences.

  - Add select-layout -E to spread panes out evenly (bound     to E key).

  - Support wide characters properly when reflowing.

  - Pass PWD to new panes as a hint to shells, as well as     calling chdir().

  - Performance improvements for the various choose modes.

  - Only show first member of session groups in tree mode     (-G flag to choose-tree to show all).

  - Support %else in config files to match %if

  - Fix 'kind' terminfo(5) capability to be S-Down not S-Up.

  - Add a box around the preview label in tree mode.

  - Show exit status and time in the remain-on-exit pane     text

  - Correctly use pane-base-index in tree mode.

  - Change the allow-rename option default to off.

  - Support for xterm(1) title stack escape sequences

  - Correctly remove padding cells to fix a UTF-8 display     problem

  - build from release tarball instead of source (drops     automake dep)

  - Bash completion is now removed and provided by

  - cleanup specfile directory with tmpfiles.d functionality     in /run/tmux

The remote Ubuntu 20.04 LTS host has a package installed that is affected by a vulnerability as referenced in the USN-4618-1 advisory.

    Sergey Nizovtsev discovered that tmux incorrectly handled some inputs. An attacker could possibly use this     issue to cause a crash or execute arbitrary code.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
191211	CentOS 9 : tmux-3.2a-4.el9	Nessus	CentOS Local Security Checks	high
149826	Photon OS 4.0: Tmux PHSA-2021-4.0-0026	Nessus	PhotonOS Local Security Checks	high
144151	EulerOS 2.0 SP8 : tmux (EulerOS-SA-2020-2537)	Nessus	Huawei Local Security Checks	high
143404	EulerOS 2.0 SP9 : tmux (EulerOS-SA-2020-2493)	Nessus	Huawei Local Security Checks	high
143402	EulerOS 2.0 SP9 : tmux (EulerOS-SA-2020-2506)	Nessus	Huawei Local Security Checks	high
142834	GLSA-202011-10 : tmux: Buffer overflow	Nessus	Gentoo Local Security Checks	high
142506	openSUSE Security Update : tmux (openSUSE-2020-1834)	Nessus	SuSE Local Security Checks	high
142501	Ubuntu 20.04 LTS : tmux vulnerability (USN-4618-1)	Nessus	Ubuntu Local Security Checks	high

Detections

Analytics

CVE-2020-27347

high

Tenable Plugins

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high

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high