{"id":"CVE-2018-21256","aliases":["EUVD-2018-13771","GHSA-7fjj-c6hx-jhxv"],"status":"published","title":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended...","description":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for group-message channel creation) via the Group message slash command.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.00615,"percentile":0.49765,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-732"],"published":"2020-06-19T17:44:07Z","modified":"2026-10-24T10:30:50Z","products":[{"vendor":"mattermost","product":"mattermost_server"}],"references":[{"url":"https://mattermost.com/security-updates/","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-21256"},{"url":"https://github.com/advisories/GHSA-7fjj-c6hx-jhxv"}],"sources":{"cve":[{"id":"CVE-2018-21256","description":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for group-message channel creation) via the Group message slash command.","status":"published","published":"2020-06-19T17:44:07Z","modified":"2024-08-05T12:26:39.427Z","updated_at":"2026-11-02T14:35:02.289647Z"}],"euvd":[{"id":"EUVD-2018-13771","description":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for group-message channel creation) via the Group message slash command.","status":"published","published":"2020-06-19T17:44:07Z","modified":"2024-08-05T12:26:39Z","updated_at":"2026-11-03T02:39:27.875919Z"}],"ghsa":[{"id":"GHSA-7fjj-c6hx-jhxv","title":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended...","description":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for group-message channel creation) via the Group message slash command.","status":"published","published":"2022-05-24T17:21:09Z","modified":"2023-01-29T05:03:22Z","updated_at":"2026-11-02T14:45:18.070616Z"}],"nvd":[{"id":"CVE-2018-21256","description":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for group-message channel creation) via the Group message slash command.","status":"published","published":"2020-06-19T18:15:10.74Z","modified":"2026-06-17T01:54:28.903Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-732"],"updated_at":"2026-11-02T14:05:00.03074Z"}],"osv":[{"id":"CVE-2018-21256","description":"An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for group-message channel creation) via the Group message slash command.","status":"published","published":"2020-06-19T18:15:10.74Z","modified":"2026-10-24T10:30:50.143378984Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:09.145458Z"}]}}