CVE-2026-82920

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-82920", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-08-31T11:19:09.113Z", "datePublished": "2026-09-14T13:59:01.993Z", "dateUpdated": "2026-09-14T19:23:01.097Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.9.0", "status": "affected", "version": "11.9.0", "versionType": "semver"}, {"lessThanOrEqual": "11.8.4", "status": "affected", "version": "11.8.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.7", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"version": "11.10.0", "status": "unaffected"}, {"version": "11.9.1", "status": "unaffected"}, {"version": "11.8.5", "status": "unaffected"}, {"version": "11.7.8", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "kiwi_71"}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N", "baseSeverity": "MEDIUM", "baseScore": 5.5}, "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-2026-00724", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00724", "defect": ["https://mattermost.atlassian.net/browse/MM-69781"], "discovery": "EXTERNAL"}, "title": "Mattermost ABAC parent policy bypass via policy update endpoint", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-09-14T13:59:01.993Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-82920", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-14T19:13:28.324125Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-14T19:23:01.097Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-82920", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-14T19:13:28.324125Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-14T19:15:26.488Z"}}], "cna": {"title": "Mattermost ABAC parent policy bypass via policy update endpoint", "source": {"defect": ["https://mattermost.atlassian.net/browse/MM-69781"], "advisory": "MMSA-2026-00724", "discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "kiwi_71"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"scope": "CHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "HIGH", "confidentialityImpact": "LOW"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "11.9.0", "versionType": "semver", "lessThanOrEqual": "11.9.0"}, {"status": "affected", "version": "11.8.0", "versionType": "semver", "lessThanOrEqual": "11.8.4"}, {"status": "affected", "version": "11.7.0", "versionType": "semver", "lessThanOrEqual": "11.7.7"}, {"status": "unaffected", "version": "11.10.0"}, {"status": "unaffected", "version": "11.9.1"}, {"status": "unaffected", "version": "11.8.5"}, {"status": "unaffected", "version": "11.7.8"}], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8 or higher."}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00724", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "descriptions": [{"lang": "en", "value": "Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724"}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-863", "description": "CWE-863: Incorrect Authorization"}]}], "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-09-14T13:59:01.993Z"}}}, "cveMetadata": {"cveId": "CVE-2026-82920", "state": "PUBLISHED", "dateUpdated": "2026-09-14T19:23:01.097Z", "dateReserved": "2026-08-31T11:19:09.113Z", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "datePublished": "2026-09-14T13:59:01.993Z", "assignerShortName": "Mattermost"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.9.0", "status": "affected", "version": "11.9.0", "versionType": "semver"}, {"lessThanOrEqual": "11.8.4", "status": "affected", "version": "11.8.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.7", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"status": "unaffected", "version": "11.10.0"}, {"status": "unaffected", "version": "11.9.1"}, {"status": "unaffected", "version": "11.8.5"}, {"status": "unaffected", "version": "11.7.8"}]}], "source": "responsibledisclosure@mattermost.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "D2DA84D0-1DE9-4846-88A0-377A6AE7FF7F", "versionEndExcluding": "11.7.8", "versionStartIncluding": "11.7.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "28B7B007-C6AE-43A8-8E34-67A52789DC27", "versionEndExcluding": "11.8.5", "versionStartIncluding": "11.8.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "AAA4200F-4BD8-4E69-A405-81E98F6208D5", "versionEndExcluding": "11.9.1", "versionStartIncluding": "11.9.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724"}], "id": "CVE-2026-82920", "lastModified": "2026-10-07T18:04:00.843", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "HIGH", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.3, "impactScore": 2.7, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-82920", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-09-14T19:13:28.324125Z", "version": "2.0.3"}}]}, "published": "2026-09-14T14:17:13.010", "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": "[11.9.0,11.9.0]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.8.0,11.8.4]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.7.0,11.7.7]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[11.10.0,11.10.0]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[11.9.1,11.9.1]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[11.8.5,11.8.5]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[11.7.8,11.7.8]"}}], "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": "2026-09-14T16:00:04.831746+00:00", "updated": "2026-09-15T14:00:11.339003+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}