CVE-2026-6342

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-6342", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-04-15T10:38:08.317Z", "datePublished": "2026-05-18T07:00:24.969Z", "dateUpdated": "2026-05-18T14:32:56.965Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.1.5", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "10.13.11", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "11.3.4", "status": "affected", "version": "0", "versionType": "semver"}, {"version": "11.6.0", "status": "unaffected"}, {"version": "11.5.2", "status": "unaffected"}, {"version": "10.11.14", "status": "unaffected"}, {"version": "11.4.4", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "eahmed"}], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601"}], "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-863: Incorrect Authorization", "cweId": "CWE-863"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00601", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost Plugins to versions 11.6.0, 11.5.2, 10.11.14, 11.4.4 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00601", "defect": ["https://mattermost.atlassian.net/browse/MM-67465"], "discovery": "EXTERNAL"}, "title": "Group prefix matching bypass for subscriptions", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-05-18T07:00:24.969Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-05-18T14:32:47.309733Z", "id": "CVE-2026-6342", "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": "2026-05-18T14:32:56.965Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-6342", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-05-18T14:32:47.309733Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-05-18T14:32:52.525Z"}}], "cna": {"title": "Group prefix matching bypass for subscriptions", "source": {"defect": ["https://mattermost.atlassian.net/browse/MM-67465"], "advisory": "MMSA-2026-00601", "discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "eahmed"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "11.1.5"}, {"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "10.13.11"}, {"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "11.3.4"}, {"status": "unaffected", "version": "11.6.0"}, {"status": "unaffected", "version": "11.5.2"}, {"status": "unaffected", "version": "10.11.14"}, {"status": "unaffected", "version": "11.4.4"}], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "Update Mattermost Plugins to versions 11.6.0, 11.5.2, 10.11.14, 11.4.4 or higher."}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00601", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601"}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-863", "description": "CWE-863: Incorrect Authorization"}]}], "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-05-18T07:00:24.969Z"}}}, "cveMetadata": {"cveId": "CVE-2026-6342", "state": "PUBLISHED", "dateUpdated": "2026-05-18T14:32:56.965Z", "dateReserved": "2026-04-15T10:38:08.317Z", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "datePublished": "2026-05-18T07:00:24.969Z", "assignerShortName": "Mattermost"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.1.5", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "10.13.11", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "11.3.4", "status": "affected", "version": "0", "versionType": "semver"}, {"status": "unaffected", "version": "11.6.0"}, {"status": "unaffected", "version": "11.5.2"}, {"status": "unaffected", "version": "10.11.14"}, {"status": "unaffected", "version": "11.4.4"}]}], "source": "responsibledisclosure@mattermost.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "52CD7965-391A-44E7-84ED-CDC9FDA780C9", "versionEndIncluding": "10.13.11", "versionStartIncluding": "10.13.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "3A2CB08F-7EC8-496F-8D14-2A608997B56E", "versionEndIncluding": "11.1.5", "versionStartIncluding": "11.1.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "BEC14053-BEB6-4E0D-BB6D-B2C114023519", "versionEndIncluding": "11.3.4", "versionStartIncluding": "11.3.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601"}, {"lang": "es", "value": "Las versiones de los plugins de Mattermost menor o igual que 11.5 11.1.5 10.13.11 11.3.4.0 no comprueban adecuadamente los espacios de nombres v\u00e1lidos, lo que permite a los usuarios de plugins crear suscripciones a grupos que no estaban en la lista blanca mediante la creaci\u00f3n de grupos que comparten el mismo prefijo que un grupo en la lista blanca. ID de aviso de Mattermost: MMSA-2026-00601"}], "id": "CVE-2026-6342", "lastModified": "2026-10-14T20:10:00.190", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 4.3, "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:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-6342", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-05-18T14:32:47.309733Z", "version": "2.0.3"}}]}, "published": "2026-05-18T08:16:14.717", "references": [{"source": "responsibledisclosure@mattermost.com", "tags": ["Vendor Advisory"], "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-863"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,11.1.5]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,10.13.11]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,11.3.4]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.6.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.5.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "10.11.14"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.4.4"}}], "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": "2026-05-18T09:30:22.295657+00:00", "updated": "2026-05-18T10:00:12.946382+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}