GHSA-3439-vqgj-2gcf
Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/mattermost/mattermost/server/v8 | >= 11.4.0-rc1, < 11.4.1 | 11.4.1 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 11.3.0-rc1, < 11.3.2 | 11.3.2 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 11.2.0-rc1, < 11.2.3 | 11.2.3 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 10.11.0-rc1, < 10.11.11 | 10.11.11 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 8.0.0-20260105080200-d27a2195068d, < 8.0.0-20260217110922-b7d4a1f1f59b | 8.0.0-20260217110922-b7d4a1f1f59b |
Details
As written in the advisory (Markdown source, shown as plain text).
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.
References
External links from the advisory. They lead to third-party sites.