{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-0999", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-01-15T15:59:41.357Z", "datePublished": "2026-02-16T09:47:45.960Z", "dateUpdated": "2026-02-17T16:53:07.181Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.1.2", "status": "affected", "version": "11.1.0", "versionType": "semver"}, {"lessThanOrEqual": "10.11.9", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"lessThanOrEqual": "11.2.1", "status": "affected", "version": "11.2.0", "versionType": "semver"}, {"version": "11.3.0", "status": "unaffected"}, {"version": "11.1.3", "status": "unaffected"}, {"version": "10.11.10", "status": "unaffected"}, {"version": "11.2.2", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "daw10"}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "baseSeverity": "MEDIUM", "baseScore": 5.4}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "description": "CWE-303: Incorrect Implementation of Authentication Algorithm", "cweId": "CWE-303"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2025-00548", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost to versions 11.3.0, 11.1.3, 10.11.10, 11.2.2 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2025-00548", "defect": ["https://mattermost.atlassian.net/browse/MM-66415"], "discovery": "EXTERNAL"}, "title": "Authentication bypass via userID login when email and username login are disabled", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-02-16T09:47:45.960Z"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-02-17T16:52:58.796354Z", "id": "CVE-2026-0999", "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": "2026-02-17T16:53:07.181Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-0999", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-02-17T16:52:58.796354Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-02-17T16:53:03.665Z"}}], "cna": {"title": "Authentication bypass via userID login when email and username login are disabled", "source": {"defect": ["https://mattermost.atlassian.net/browse/MM-66415"], "advisory": "MMSA-2025-00548", "discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "daw10"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.4, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "11.1.0", "versionType": "semver", "lessThanOrEqual": "11.1.2"}, {"status": "affected", "version": "10.11.0", "versionType": "semver", "lessThanOrEqual": "10.11.9"}, {"status": "affected", "version": "11.2.0", "versionType": "semver", "lessThanOrEqual": "11.2.1"}, {"status": "unaffected", "version": "11.3.0"}, {"status": "unaffected", "version": "11.1.3"}, {"status": "unaffected", "version": "10.11.10"}, {"status": "unaffected", "version": "11.2.2"}], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "Update Mattermost to versions 11.3.0, 11.1.3, 10.11.10, 11.2.2 or higher."}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2025-00548", "tags": ["vendor-advisory"]}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548"}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-303", "description": "CWE-303: Incorrect Implementation of Authentication Algorithm"}]}], "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-02-16T09:47:45.960Z"}}}, "cveMetadata": {"cveId": "CVE-2026-0999", "state": "PUBLISHED", "dateUpdated": "2026-02-17T16:53:07.181Z", "dateReserved": "2026-01-15T15:59:41.357Z", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "datePublished": "2026-02-16T09:47:45.960Z", "assignerShortName": "Mattermost"}, "dataVersion": "5.2"}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "92B0F8BD-06A1-4B39-95C5-4FB5A195F1C4", "versionEndExcluding": "10.11.10", "versionStartIncluding": "10.11.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "F28AD5DC-E336-4DD3-BC31-AC924190433C", "versionEndExcluding": "11.1.3", "versionStartIncluding": "11.1.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "D98EAFB2-8055-4893-835B-30A99ED97892", "versionEndExcluding": "11.2.2", "versionStartIncluding": "11.2.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548"}, {"lang": "es", "value": "Las versiones de Mattermost 11.1.x &lt;= 11.1.2, 10.11.x &lt;= 10.11.9, 11.2.x &lt;= 11.2.1 no validan correctamente las restricciones del m\u00e9todo de inicio de sesi\u00f3n, lo que permite a un usuario autenticado eludir los requisitos de inicio de sesi\u00f3n solo por SSO mediante autenticaci\u00f3n basada en ID de usuario. ID de aviso de Mattermost: MMSA-2025-00548"}], "id": "CVE-2026-0999", "lastModified": "2026-02-18T20:20:07.833", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.5, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}, {"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": "nvd@nist.gov", "type": "Primary"}]}, "published": "2026-02-16T10:16:08.140", "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-303"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

{}