{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-96259", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-09-22T19:59:57.887Z", "datePublished": "2026-09-22T20:34:20.872Z", "dateUpdated": "2026-09-22T20:34:20.872Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.9.1", "status": "affected", "version": "11.9.0", "versionType": "semver"}, {"lessThanOrEqual": "11.8.5", "status": "affected", "version": "11.8.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.10", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"lessThanOrEqual": "11.10.1", "status": "affected", "version": "11.10.0", "versionType": "semver"}, {"version": "11.11.0", "status": "unaffected"}, {"version": "11.9.2", "status": "unaffected"}, {"version": "11.8.6", "status": "unaffected"}, {"version": "11.7.11", "status": "unaffected"}, {"version": "11.10.2", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "n1nj4sec"}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776"}], "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-918: Server-Side Request Forgery (SSRF)", "cweId": "CWE-918"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00776", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00776", "defect": ["https://mattermost.atlassian.net/browse/MM-70502"], "discovery": "EXTERNAL"}, "title": "Mattermost server-side request forgery via OAuth endpoints configurable by a System Administrator", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-09-22T20:34:20.872Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.9.1", "status": "affected", "version": "11.9.0", "versionType": "semver"}, {"lessThanOrEqual": "11.8.5", "status": "affected", "version": "11.8.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.10", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"lessThanOrEqual": "11.10.1", "status": "affected", "version": "11.10.0", "versionType": "semver"}, {"status": "unaffected", "version": "11.11.0"}, {"status": "unaffected", "version": "11.9.2"}, {"status": "unaffected", "version": "11.8.6"}, {"status": "unaffected", "version": "11.7.11"}, {"status": "unaffected", "version": "11.10.2"}]}], "source": "responsibledisclosure@mattermost.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776"}], "id": "CVE-2026-96259", "lastModified": "2026-09-22T21:17:34.910", "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"}]}, "published": "2026-09-22T21:17:34.910", "references": [{"source": "responsibledisclosure@mattermost.com", "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-918"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.9.0,11.9.1]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.8.0,11.8.5]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.7.0,11.7.10]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.10.0,11.10.1]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.11.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.9.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.8.6"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.7.11"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.10.2"}}], "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": "2026-09-22T21:30:19.304491+00:00", "updated": "2026-09-22T21:30:20.111733+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}