{"id":"CVE-2026-18223","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-18223","generatedAt":"2026-10-28T01:12:32.807Z","title":"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 validate the invited recipient's email address when redeeming team and guest invitation tokens, which allows an authenticated attacker to join a team or…","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 validate the invited recipient's email address when redeeming team and guest invitation tokens, which allows an authenticated attacker to join a team or gain unauthorized access to private channels via a forwarded or leaked invitation link.. Mattermost Advisory ID: MMSA-2026-00747","published":"2026-10-16T08:17:13.000Z","lastModified":"2026-10-16T19:23:19.000Z","status":"Awaiting Analysis","sourceIdentifier":"responsibledisclosure@mattermost.com","cvss":{"version":"3.1","score":5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N"},"cwe":["CWE-863"],"affected":[],"epss":{"score":0.00161,"percentile":0.05196,"date":"2026-10-26","history":[{"date":"2026-10-16","score":0.00161,"percentile":0.04814}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.16%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-16T08:17:13.000Z","detail":{"score":"5.0","severity":"MEDIUM","publishedAt":"2026-10-16T08:17:12.753Z"},"summary":"New CVE, medium severity (CVSS 5.0)."}],"references":[{"url":"https://mattermost.com/security-updates","source":"responsibledisclosure@mattermost.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-18223","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}