CVE-2026-5139

{"id": "CVE-2026-5139", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-5139", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-06-22T15:39:17.436366Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "cvssData": {"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:N/I:L/A:L", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 2.5, "exploitabilityScore": 2.8}]}, "affected": [{"source": "responsibledisclosure@mattermost.com", "affectedData": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "11.7.0", "versionType": "semver", "lessThanOrEqual": "11.7.0"}, {"status": "affected", "version": "11.6.0", "versionType": "semver", "lessThanOrEqual": "11.6.2"}, {"status": "affected", "version": "11.5.0", "versionType": "semver", "lessThanOrEqual": "11.5.5"}, {"status": "affected", "version": "10.11.0", "versionType": "semver", "lessThanOrEqual": "10.11.17"}, {"status": "unaffected", "version": "11.8.0"}, {"status": "unaffected", "version": "11.7.1"}, {"status": "unaffected", "version": "11.6.3"}, {"status": "unaffected", "version": "11.5.6"}, {"status": "unaffected", "version": "10.11.18"}], "defaultStatus": "unaffected"}]}], "published": "2026-06-22T14:17:50.887", "references": [{"url": "https://mattermost.com/security-updates", "tags": ["Vendor Advisory"], "source": "responsibledisclosure@mattermost.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "description": [{"lang": "en", "value": "CWE-862"}]}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644"}], "lastModified": "2026-06-23T20:50:51.550", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "96DE4802-EC1E-43F1-BA75-6645A6EE12FF", "versionEndExcluding": "10.11.18", "versionStartIncluding": "10.11.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DE6925FD-7708-4A31-A240-087199E4A907", "versionEndExcluding": "11.5.6", "versionStartIncluding": "11.5.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1D3AEA32-BA45-409E-BF12-47F253639A6E", "versionEndExcluding": "11.6.3", "versionStartIncluding": "11.6.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5B5CE3FF-EE89-4013-821B-3ED4A48B4352", "versionEndExcluding": "11.7.1", "versionStartIncluding": "11.7.0"}], "operator": "OR"}]}], "sourceIdentifier": "responsibledisclosure@mattermost.com"}