GitHub OAuth Scope Validation_CVE-2026-28735

{
    "lastseen": "",
    "description": "Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the OAuth token scope on the callback which allows an authenticated Mattermost user to gain access to private repositories via modifying the scope parameter in the GitHub authorization URL.. Mattermost Advisory ID: MMSA-2026-00628",
    "published": "2026-05-22T16:26:04.066Z",
    "modified": "2026-05-22T16:26:04.066Z",
    "type": "cve",
    "title": "GitHub OAuth Scope Validation",
    "source": "Mattermost",
    "references": "https://mattermost.com/security-updates",
    "id": "CVE-2026-28735",
    "bulletinFamily": "",
    "cwe": [
        "CWE-863"
    ],
    "cvelist": null,
    "sourceData": "Mattermost Mattermost 11.6.0\nMattermost Mattermost 11.5.0\nMattermost Mattermost 11.4.0\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:L/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
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            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Mattermost",
    "version": "11.6.0",
    "vendor": "Mattermost",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}