Vulnerability · Published Mar 26, 2026 · Assigned by Mattermost
CVE-2026-3108Terminal Escape Injection in mmctl Report Posts Command
High 8.0
In plain English
A high-severity security flaw in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.11.11+incompatible, 11.2.3+incompatible, 11.3.2+incompatible, 11.4.1+incompatible | GO-2026-5067 |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2026-5067 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2026-5067 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.11 | GHSA-3439-vqgj-2gcf |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260217110922-b7d4a1f1f59b | GHSA-3439-vqgj-2gcf |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.1 | GHSA-3439-vqgj-2gcf |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260217110922-b7d4a1f1f59b | GO-2026-5067 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.3.2 | GHSA-3439-vqgj-2gcf |
| Go | github.com/mattermost/mattermost/server/v8 | 11.2.3 | GHSA-3439-vqgj-2gcf |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.2.0 – through 11.2.210.11.0 – through 10.11.1011.4.0 – through 11.4.011.3.0 – through 11.3.1 |
Weakness: CWE-150 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
References
- MMSA-2026-00599 vendor-advisory