{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-16044", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-07-17T09:40:22.350Z", "datePublished": "2026-08-17T14:26:52.203Z", "dateUpdated": "2026-08-17T15:25:51.740Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.7.6", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"lessThanOrEqual": "10.11.21", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"version": "11.9.0", "status": "unaffected"}, {"version": "11.7.7", "status": "unaffected"}, {"version": "10.11.22", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "ilent0"}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00672"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L", "baseSeverity": "LOW", "baseScore": 3.9}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "description": "CWE-863: Incorrect Authorization", "cweId": "CWE-863"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00672", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost to versions 11.9.0, 11.7.7, 10.11.22 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00672", "defect": ["https://mattermost.atlassian.net/browse/MM-68825"], "discovery": "EXTERNAL"}, "title": "Insufficient validation of guest board admin privileges on archive import", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-08-17T14:26:52.203Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-08-17T14:50:45.509454Z", "id": "CVE-2026-16044", "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": "2026-08-17T15:25:51.740Z"}}]}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.7.6", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"lessThanOrEqual": "10.11.21", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"status": "unaffected", "version": "11.9.0"}, {"status": "unaffected", "version": "11.7.7"}, {"status": "unaffected", "version": "10.11.22"}]}], "source": "responsibledisclosure@mattermost.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00672"}], "id": "CVE-2026-16044", "lastModified": "2026-08-17T15:16:53.857", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.5, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}, "published": "2026-08-17T15:16:53.857", "references": [{"source": "responsibledisclosure@mattermost.com", "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-863"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.7.0,11.7.6]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[10.11.0,10.11.21]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.9.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.7.7"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "10.11.22"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Mattermost", "source": "cna", "vendor": "Mattermost"}, "product": "mattermost", "vendor": "mattermost"}], "created": "2026-08-17T15:30:06.103243+00:00", "updated": "2026-08-17T15:30:06.281283+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}