{"id":"CVE-2018-21255","details":"An issue was discovered in Mattermost Server before 5.1. Non-members of a channel could use the Channel PATCH API to modify that channel.","modified":"2026-07-08T19:45:33.169165Z","published":"2020-06-19T17:15:12.663Z","references":[{"type":"ADVISORY","url":"https://mattermost.com/security-updates/"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost","events":[{"introduced":"0"},{"fixed":"54994502241bf40bebd9a9d7719c58f708aef5b1"}],"database_specific":{"cpe":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"5.1.0"}],"source":"CPE_RANGE"}}],"versions":["v5.1.0-rc3","v5.1.0-rc2","v5.1.0-rc1","v5.0.0-rc1","v4.10.0-rc1","v4.9.0-rc1","v4.8.0-rc1","v4.7.0-rc1","v4.6.0-rc2","v4.6.0-rc1","v4.5.0-rc1","v4.4.0-rc1","v4.3.0-rc1","v4.2.0-rc1","v0.5.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-21255.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"}]}