{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-9693", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-05-27T10:58:39.051Z", "datePublished": "2026-08-17T22:07:12.958Z", "dateUpdated": "2026-08-17T22:07:12.958Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "10.11.20", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.5", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"version": "11.9.0", "status": "unaffected"}, {"version": "10.11.21", "status": "unaffected"}, {"version": "11.7.6", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "kiwi_71"}], "descriptions": [{"lang": "en", "value": "Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N", "baseSeverity": "LOW", "baseScore": 3.5}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "description": "CWE-459: Incomplete Cleanup", "cweId": "CWE-459"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00682", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost to versions 11.9.0, 10.11.21, 11.7.6 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00682", "defect": ["https://mattermost.atlassian.net/browse/MM-69006"], "discovery": "EXTERNAL"}, "title": "Mattermost thread memberships persist after team removal, exposing private channel thread metadata on re-invite", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-08-17T22:07:12.958Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "10.11.20", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.5", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"status": "unaffected", "version": "11.9.0"}, {"status": "unaffected", "version": "10.11.21"}, {"status": "unaffected", "version": "11.7.6"}]}], "source": "responsibledisclosure@mattermost.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682"}], "id": "CVE-2026-9693", "lastModified": "2026-08-17T23:16:52.940", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 3.5, "baseSeverity": "LOW", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 2.1, "impactScore": 1.4, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}, "published": "2026-08-17T23:16:52.940", "references": [{"source": "responsibledisclosure@mattermost.com", "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-459"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[10.11.0,10.11.20]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.7.0,11.7.5]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.9.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "10.11.21"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.7.6"}}], "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": "2026-08-17T23:30:04.672011+00:00", "updated": "2026-08-18T01:00:05.238381+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}