{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-6957", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-04-24T13:23:50.185Z", "datePublished": "2026-05-27T14:23:50.770Z", "dateUpdated": "2026-05-27T14:23:50.770Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "1.1.5", "status": "affected", "version": "0", "versionType": "semver"}, {"version": ".0", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "Hassan Mohammed"}], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which allows an administrator of a remote federated Mattermost server to write files to arbitrary locations within the target server's filestore via a malicious filename delivered through the shared-channel attachment sync protocol. Mattermost Advisory ID: MMSA-2026-00659"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseSeverity": "HIGH", "baseScore": 8}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", "cweId": "CWE-22"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00659", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost Plugins to versions .0 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00659", "defect": ["https://mattermost.atlassian.net/browse/MM-68411"], "discovery": "{\"self\"=>\"https://mattermost.atlassian.net/rest/api/2/customFieldOption/10557\", \"value\"=>\"Internal\", \"id\"=>\"10557\"}"}, "title": "Path traversal in Mattermost Legal Hold plugin via unsanitized file name from federated peer allows arbitrary file write.", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-05-27T14:23:50.770Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which allows an administrator of a remote federated Mattermost server to write files to arbitrary locations within the target server's filestore via a malicious filename delivered through the shared-channel attachment sync protocol. Mattermost Advisory ID: MMSA-2026-00659"}], "id": "CVE-2026-6957", "lastModified": "2026-05-27T15:16:34.903", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.0, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.3, "impactScore": 6.0, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}, "published": "2026-05-27T15:16:34.903", "references": [{"source": "responsibledisclosure@mattermost.com", "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-22"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

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