Skip to content
Fencer Vulns
high 8.8

CVE-2020-27347 json

tmux stack buffer overflow in function input_csi_dispatch_sgr_colon

published 2020-11-06 6 y ago modified 2026-07-25 3 mo ago also EUVD-2020-19860 , JLSEC-2026-528

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

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.

Patch / fix

  • julia tmux_jll 3.3.0+0
  • tmux tmux 3.1c
  • Ubuntu tmux 3.0a-2ubuntu0.2, 3.1b-1ubuntu0.1
  • tmux Debian 14, Debian 13, Debian 12 3.1c-1

debian advisories DEBIAN-CVE-2020-27347

  • tmux Ubuntu 20.04 LTS 3.0a-2ubuntu0.2

ubuntu advisories UBUNTU-CVE-2020-27347

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tmux openSUSE Tumbleweed 3.2a-1.2
  • tmux Package Hub 15 SP2, Package Hub 15 SP1, Package Hub 12 +2 more 3.1c-bp152.2.3.1

opensuse advisories openSUSE-SU-2024:11466-1openSUSE-SU-2020:1834-1

  • tmux Alpine 3.10 2.9a-r2
  • tmux Alpine 3.11 3.0a-r2
  • tmux Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 3.1c-r0

alpine advisories ALPINE-CVE-2020-27347

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-27347 updated cvss 8.5

tmux: stack buffer overflow in input_csi_dispatch_sgr_colon

  • Red Hat Enterprise Linux 7 tmux Red Hat Enterprise Linux 8 tmux Red Hat Enterprise Linux 9 tmux
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com https://www.openwall.com/lists/oss-security/2020/11/05/3 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P
OSV 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia tmux_jll
<3.3.0+0
3.3.0+0

Affected products

  • tmux tmux
  • Ubuntu tmux

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.