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Fencer Vulns
high 8.0

CVE-2026-3108 json

Terminal Escape Injection in mmctl Report Posts Command

published 2026-03-26 7 mo ago modified 2026-06-25 4 mo ago also GHSA-3439-vqgj-2gcf , GO-2026-5067 , EUVD-2026-16234

cvss
8.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to sanitize user-controlled post content in the mmctl commands terminal output which allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences that enable screen manipulation, fake prompts, and clipboard hijacking.. Mattermost Advisory ID: MMSA-2026-00599

Patch / fix

  • go github.com/mattermost/mattermost/server/v8 8.0.0-20260217110922-b7d4a1f1f59b, 10.11.11, 11.2.3, 11.3.2, 11.4.1
  • go github.com/mattermost/mattermost-server 10.11.11+incompatible, 11.2.3+incompatible, 11.3.2+incompatible, 11.4.1+incompatible
  • Mattermost Mattermost 10.11.11, 11.2.3, 11.3.2, 11.4.1, 11.5.0
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

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-2026-3108 updated cvss 8.9

Mattermost: mmctl: Mattermost mmctl: Administrator terminal manipulation via crafted messages

  • Red Hat All currently supported Red Hat products
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.0 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.0 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/mattermost/mattermost/server/v8
>=11.4.0-rc1, <11.4.1
>=11.3.0-rc1, <11.3.2
>=11.2.0-rc1, <11.2.3
>=10.11.0-rc1, <10.11.11
>=8.0.0-20260105080200-d27a2195068d, <8.0.0-20260217110922-b7d4a1f1f59b
11.4.1
11.3.2
11.2.3
10.11.11
8.0.0-20260217110922-b7d4a1f1f59b
go github.com/mattermost/mattermost-server
>=10.11.0-rc1+incompatible, <10.11.11+incompatible
>=11.2.0-rc1+incompatible, <11.2.3+incompatible
>=11.3.0-rc1+incompatible, <11.3.2+incompatible
>=11.4.0-rc1+incompatible, <11.4.1+incompatible
10.11.11+incompatible
11.2.3+incompatible
11.3.2+incompatible
11.4.1+incompatible
go github.com/mattermost/mattermost-server/v5
all versions
 no fix listed
go github.com/mattermost/mattermost-server/v6
all versions
 no fix listed

Affected products

  • Mattermost Mattermost

Classification

Weakness
  • CWE-150 Improper Neutralization of Escape, Meta, or Control Sequences

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.