CVE-2026-18223Medium· 5.0▾ SunlitMattermost 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 t…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 27.5 · likelihood 0 · exploitation 0
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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
Mattermost >= 11.10.0 <= 11.10.0Mattermost >= 11.7.0 <= 11.7.9Mattermost >= 11.9.0 <= 11.9.1Mattermost >= 11.8.0 <= 11.8.5Update Mattermost to versions 11.11.0, 11.10.1, 11.7.10, 11.9.2, 11.8.6 or higher.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-18551Medium· 6.5Mattermost guest account privilege escalation via member roles API
CVE-2026-19076Medium· 4.4Mattermost fails to reject OAuth application sessions in account type switch, allowing account takeover via bearer token
CVE-2026-18256Medium· 4.3Private team metadata disclosure via the team search API
CVE-2026-19541Medium· 6.5Outgoing OAuth connection client secret exposure during connection validation
CVE-2026-19601Medium· 4.9Disclosure of AD/LDAP bind password via Test Connection
CVE-2026-19867Medium· 4.3Uncapped mention keys in user notification properties allow CPU exhaustion during post processing