{"id":"CVE-2018-21257","details":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for setting a channel header) via the Channel header slash command API.","modified":"2026-03-12T22:51:19.506800Z","published":"2020-06-19T17:15:12.740Z","references":[{"type":"ADVISORY","url":"https://mattermost.com/security-updates/"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost-server","events":[{"introduced":"0"},{"fixed":"54994502241bf40bebd9a9d7719c58f708aef5b1"}],"database_specific":{"versions":[{"introduced":"0"},{"fixed":"5.1.0"}]}}],"versions":["v0.5.0","v0.6.0","v1.0.0","v1.1.0","v1.1.1","v1.2.1","v1.3.0","v1.4.0","v2.0.0","v3.0.0","v3.0.1","v3.0.2","v3.0.3","v3.1.0","v3.2.0","v3.3.0","v3.4.0","v3.5.0","v3.5.1","v3.6.0","v3.6.1","v3.7.0","v3.7.1","v3.7.2","v3.7.3","v3.8.0","v4.0.0","v4.0.1","v4.1.0","v4.10.0","v4.10.0-rc1","v4.10.0-rc2","v4.10.0-rc3","v4.10.0-rc4","v4.10.0-rc5","v4.2.0-rc1","v4.3.0","v4.3.0-rc1","v4.3.0-rc2","v4.3.0-rc3","v4.3.0-rc4","v4.4.0","v4.4.0-rc1","v4.4.0-rc2","v4.4.0-rc3","v4.4.0-rc4","v4.4.0-rc5","v4.5.0","v4.5.0-rc1","v4.5.0-rc2","v4.5.0-rc3","v4.5.0-rc4","v4.5.1","v4.5.1-rc1","v4.5.2","v4.5.2-rc1","v4.6.0","v4.6.0-rc1","v4.6.0-rc2","v4.6.0-rc3","v4.6.0-rc4","v4.6.0-rc5","v4.6.0-rc6","v4.7.0","v4.7.0-rc1","v4.7.0-rc2","v4.7.0-rc3","v4.7.0-rc4","v4.7.1","v4.7.1-rc1","v4.7.2","v4.7.2-rc1","v4.7.2-rc2","v4.7.2-rc3","v4.7.3","v4.7.3-rc1","v4.8.0","v4.8.0-rc1","v4.8.0-rc2","v4.8.0-rc3","v4.8.0-rc4","v4.8.0-rc5","v4.8.0-rc6","v4.9.0","v4.9.0-rc1","v4.9.0-rc2","v4.9.0-rc3","v4.9.0-rc4","v4.9.0-rc5","v4.9.0-rc6","v5.0.0","v5.0.0-rc1","v5.0.0-rc2","v5.0.0-rc3","v5.0.0-rc4","v5.0.0-rc5","v5.0.0-rc6","v5.0.0-rc7","v5.0.1","v5.0.1-rc1","v5.1.0-rc1","v5.1.0-rc2","v5.1.0-rc3"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2018-21257.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}