CVE-2026-3108 — Improper Neutralization of Escape, Meta, or Control Sequences in Mattermost Mattermost Server V8

CWE-150 — Improper Neutralization of Escape, Meta, or Control Sequences5 documents5 sources
Severity
8.8HIGHNVD
CNA8.0
EPSS
0.0%
top 87.43%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Github.com Mattermost Mattermost Server V8Mattermost ServerMattermost
Timeline
PublishedMar 26

Description

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

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitability: 2.8 | Impact: 5.9

Affected Packages3 packages

▶NVDmattermost/mattermost_server10.11.0 — 10.11.11+3
▶Gogithub.com/mattermost_mattermost_server_v811.4.0-rc1 — 11.4.1+4
▶CVEListV5mattermost/mattermost11.2.0 — 11.2.2+3

🔴Vulnerability Details

3
CVEList
Terminal Escape Injection in mmctl Report Posts Command↗2026-03-26
▶
GHSA
Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences↗2026-03-26
▶
OSV
Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences↗2026-03-26
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-3108 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶
CVE-2026-3108 — HIGH severity | cvebase