GHSA-3439-VQGJ-2GCF

Vulnerability from github – Published: 2026-03-26 18:31 – Updated: 2026-03-31 23:02
VLAI
Summary
Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences
Details

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.

Severity
8.0 (High)
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.4.0-rc1"
            },
            {
              "fixed": "11.4.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.3.0-rc1"
            },
            {
              "fixed": "11.3.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.2.0-rc1"
            },
            {
              "fixed": "11.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.11.0-rc1"
            },
            {
              "fixed": "10.11.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0-20260105080200-d27a2195068d"
            },
            {
              "fixed": "8.0.0-20260217110922-b7d4a1f1f59b"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-3108"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-150"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-31T23:02:43Z",
    "nvd_published_at": "2026-03-26T17:16:41Z",
    "severity": "HIGH"
  },
  "details": "Mattermost versions 11.2.x \u003c= 11.2.2, 10.11.x \u003c= 10.11.10, 11.4.x \u003c= 11.4.0, 11.3.x \u003c= 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.",
  "id": "GHSA-3439-vqgj-2gcf",
  "modified": "2026-03-31T23:02:57Z",
  "published": "2026-03-26T18:31:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3108"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost/mattermost"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences"
}



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