{"id":"CVE-2026-18799","revision":"dc88dd57bcd94ab9abaa450913b94539","records":[{"revision":"dc88dd57bcd94ab9abaa450913b94539","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-18799","aliases":[],"title":"Mattermost Server fails to restrict Slack import account binding, allowing team admins to forge posts as existing users","description":"Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to restrict Slack import account binding to system administrator-initiated imports which allows an authenticated attacker with team admin privileges to force-add existing Mattermost users to their team and forge posts attributed to those users' identities via a crafted Slack export containing target users' email addresses.. Mattermost Advisory ID: MMSA-2026-00757","state":0,"publishedAt":"2026-10-16T07:16:19.062+00:00","modifiedAt":"2026-10-16T11:28:45.2+00:00","affected":[{"ecosystem":"Vendor product","name":"Mattermost","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"defaultStatus\": \"unaffected\",\n                    \"product\": \"Mattermost\",\n                    \"vendor\": \"Mattermost\",\n                    \"versions\": [\n                        {\n                            \"lessThanOrEqual\": \"11.10.0\",\n                            \"status\": \"affected\",\n                            \"version\": \"11.10.0\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"lessThanOrEqual\": \"11.7.9\",\n                            \"status\": \"affected\",\n                            \"version\": \"11.7.0\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"lessThanOrEqual\": \"11.9.1\",\n                            \"status\": \"affected\",\n                            \"version\": \"11.9.0\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"lessThanOrEqual\": \"11.8.5\",\n                            \"status\": \"affected\",\n                            \"version\": \"11.8.0\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"11.11.0\",\n                            \"status\": \"unaffected\"\n                        },\n                        {\n                            \"version\": \"11.10.1\",\n                            \"status\": \"unaffected\"\n                        },\n                        {\n                            \"version\": \"11.7.10\",\n                            \"status\": \"unaffected\"\n                        },\n                        {\n                            \"version\": \"11.9.2\",\n                            \"status\": \"unaffected\"\n                        },\n                        {\n                            \"version\": \"11.8.6\",\n                            \"status\": \"unaffected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","score":4.3,"severity":"MEDIUM"}],"references":["https://mattermost.com/security-updates"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-18799","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-18799","identifiers":["CVE-2026-18799"]},"retained":false,"historicalAffected":[]}],"coverage":[]}