{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-18799",
        "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "state": "PUBLISHED",
        "assignerShortName": "Mattermost",
        "dateReserved": "2026-08-04T10:05:23.880Z",
        "datePublished": "2026-10-16T07:16:19.062Z",
        "dateUpdated": "2026-10-16T11:28:45.200Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "defaultStatus": "unaffected",
                    "product": "Mattermost",
                    "vendor": "Mattermost",
                    "versions": [
                        {
                            "lessThanOrEqual": "11.10.0",
                            "status": "affected",
                            "version": "11.10.0",
                            "versionType": "semver"
                        },
                        {
                            "lessThanOrEqual": "11.7.9",
                            "status": "affected",
                            "version": "11.7.0",
                            "versionType": "semver"
                        },
                        {
                            "lessThanOrEqual": "11.9.1",
                            "status": "affected",
                            "version": "11.9.0",
                            "versionType": "semver"
                        },
                        {
                            "lessThanOrEqual": "11.8.5",
                            "status": "affected",
                            "version": "11.8.0",
                            "versionType": "semver"
                        },
                        {
                            "version": "11.11.0",
                            "status": "unaffected"
                        },
                        {
                            "version": "11.10.1",
                            "status": "unaffected"
                        },
                        {
                            "version": "11.7.10",
                            "status": "unaffected"
                        },
                        {
                            "version": "11.9.2",
                            "status": "unaffected"
                        },
                        {
                            "version": "11.8.6",
                            "status": "unaffected"
                        }
                    ]
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "type": "finder",
                    "value": "Claude and Ada Logics"
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to restrict Slack import account binding to system administrator-initiated imports which allows an authenticated attacker with team admin privileges to force-add existing Mattermost users to their team and forge posts attributed to those users' identities via a crafted Slack export containing target users' email addresses.. Mattermost Advisory ID: MMSA-2026-00757"
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "LOW",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "LOW",
                        "availabilityImpact": "NONE",
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
                        "baseSeverity": "MEDIUM",
                        "baseScore": 4.3
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "type": "CWE",
                            "description": "CWE-862: Missing Authorization",
                            "cweId": "CWE-862"
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://mattermost.com/security-updates",
                    "name": "MMSA-2026-00757",
                    "tags": [
                        "vendor-advisory"
                    ]
                }
            ],
            "solutions": [
                {
                    "value": "Update Mattermost to versions 11.11.0, 11.10.1, 11.7.10, 11.9.2, 11.8.6 or higher.",
                    "lang": "en"
                }
            ],
            "source": {
                "advisory": "MMSA-2026-00757",
                "defect": [
                    "https://mattermost.atlassian.net/browse/MM-70095"
                ],
                "discovery": "EXTERNAL"
            },
            "title": "Mattermost Server fails to restrict Slack import account binding, allowing team admins to forge posts as existing users",
            "providerMetadata": {
                "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
                "shortName": "Mattermost",
                "dateUpdated": "2026-10-16T07:16:19.062Z"
            },
            "x_generator": {
                "engine": "cvelib 1.8.0"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-16T11:28:31.537040Z",
                                "id": "CVE-2026-18799",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-16T11:28:45.200Z"
                }
            }
        ]
    }
}