{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-12284", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-06-15T14:05:20.532Z", "datePublished": "2026-09-17T15:11:52.297Z", "dateUpdated": "2026-09-17T19:18:45.112Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "6.2.2", "status": "affected", "version": "0", "versionType": "semver"}, {"version": "6.3.0", "status": "unaffected"}, {"version": "6.2.3.0", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "Juho Fors\u00e9n"}], "descriptions": [{"lang": "en", "value": "Mattermost Desktop App versions <=6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server (or a user with script access to a connected server view) to disconnect an active call belonging to a different connected server via the desktopAPI.leaveCall IPC message. Mattermost Advisory ID: MMSA-2026-00699"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L", "baseSeverity": "LOW", "baseScore": 3.8}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "description": "CWE-346: Origin Validation Error", "cweId": "CWE-346"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00699", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost Desktop App to versions 6.3.0, 6.2.3.0 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00699", "defect": ["https://mattermost.atlassian.net/browse/MM-69153"], "discovery": "{\"self\"=>\"https://mattermost.atlassian.net/rest/api/2/customFieldOption/10557\", \"value\"=>\"Internal\", \"id\"=>\"10557\"}"}, "title": "Mattermost Desktop App Missing IPC Sender Validation in Calls Leave Handler", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-09-17T15:11:52.297Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-09-17T19:18:33.462460Z", "id": "CVE-2026-12284", "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": "2026-09-17T19:18:45.112Z"}}]}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "6.2.2", "status": "affected", "version": "0", "versionType": "semver"}, {"status": "unaffected", "version": "6.3.0"}, {"status": "unaffected", "version": "6.2.3.0"}]}], "source": "[email protected]"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost Desktop App versions <=6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server (or a user with script access to a connected server view) to disconnect an active call belonging to a different connected server via the desktopAPI.leaveCall IPC message. Mattermost Advisory ID: MMSA-2026-00699"}], "id": "CVE-2026-12284", "lastModified": "2026-09-17T20:16:49.053", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 3.7, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 1.4, "source": "[email protected]", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-12284", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-09-17T19:18:33.462460Z", "version": "2.0.3"}}]}, "published": "2026-09-17T16:17:21.993", "references": [{"source": "[email protected]", "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-346"}], "source": "[email protected]", "type": "Secondary"}]}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,6.2.2]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "6.3.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "6.2.3.0"}}], "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": "2026-09-17T19:30:06.267018+00:00", "updated": "2026-09-17T19:30:06.267041+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}