GitLab Plugin Allows Non-Admin Users to Modify Default Instance Configuration_CVE-2026-5139

{
    "lastseen": "",
    "description": "Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644",
    "published": "2026-06-22T13:34:21.247Z",
    "modified": "2026-06-22T13:34:21.247Z",
    "type": "cve",
    "title": "GitLab Plugin Allows Non-Admin Users to Modify Default Instance Configuration",
    "source": "Mattermost",
    "references": "https://mattermost.com/security-updates",
    "id": "CVE-2026-5139",
    "bulletinFamily": "",
    "cwe": [
        "CWE-862"
    ],
    "cvelist": null,
    "sourceData": "Mattermost Mattermost 11.7.0\nMattermost Mattermost 11.6.0\nMattermost Mattermost 11.5.0\nMattermost Mattermost 10.11.0",
    "sourceHref": "",
    "cvss": {
        "score": 5.4,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
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    "product": "Mattermost",
    "version": "11.7.0",
    "vendor": "Mattermost",
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}