CVE-2026-6850

{"id": "CVE-2026-6850", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-6850", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-13T13:56:09.905130Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.8}]}, "affected": [{"source": "responsibledisclosure@mattermost.com", "affectedData": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "11.7.0", "versionType": "semver", "lessThanOrEqual": "11.7.2"}, {"status": "affected", "version": "11.6.0", "versionType": "semver", "lessThanOrEqual": "11.6.4"}, {"status": "affected", "version": "10.11.0", "versionType": "semver", "lessThanOrEqual": "10.11.19"}, {"status": "unaffected", "version": "11.8.0"}, {"status": "unaffected", "version": "11.7.3"}, {"status": "unaffected", "version": "11.6.5"}, {"status": "unaffected", "version": "10.11.20"}], "defaultStatus": "unaffected"}]}], "published": "2026-07-13T09:16:24.890", "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-1333"}]}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate the length and content of message attachment field values, which allows an authenticated attacker to cause a denial of service for all users in a channel via a post containing a specially crafted payload that triggers catastrophic backtracking in the client-side markdown parser.. Mattermost Advisory ID: MMSA-2026-00658"}], "lastModified": "2026-07-13T21:42:01.650", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "806B772A-4575-47F4-BD6B-7422C9045190", "versionEndExcluding": "10.11.20", "versionStartIncluding": "10.11.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2B2D3A05-5A6F-4121-80BE-6DC87A30C354", "versionEndExcluding": "11.6.5", "versionStartIncluding": "11.6.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "61277B68-8856-4C8A-97CC-E37742682A4B", "versionEndExcluding": "11.7.3", "versionStartIncluding": "11.7.0"}], "operator": "OR"}]}], "sourceIdentifier": "responsibledisclosure@mattermost.com"}