{"schema_version":"1.7.3","id":"GHSA-gg42-mwr6-p82c","published":"2022-05-24T17:21:05Z","modified":"2026-02-03T03:02:41.212210Z","aliases":["CVE-2017-18894","GO-2026-4297"],"summary":"Mattermost Server has intermittent Authorization bypass for resource-owners","details":"An issue was discovered in Mattermost Server before 4.2.0, 4.1.1, and 4.0.5, when used as an OAuth 2.0 service provider. Resource-owner authorization can be intermittently bypassed, allowing account takeover.","affected":[{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.0.5"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/05/GHSA-gg42-mwr6-p82c/GHSA-gg42-mwr6-p82c.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.1.0"},{"fixed":"4.1.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/05/GHSA-gg42-mwr6-p82c/GHSA-gg42-mwr6-p82c.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.2.0-rc1"},{"fixed":"4.2.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/05/GHSA-gg42-mwr6-p82c/GHSA-gg42-mwr6-p82c.json"}}],"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2017-18894"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost"},{"type":"WEB","url":"https://mattermost.com/security-updates"}],"database_specific":{"cwe_ids":["CWE-639","CWE-732"],"github_reviewed":true,"github_reviewed_at":"2026-01-12T18:34:33Z","nvd_published_at":"2020-06-19T19:15:00Z","severity":"HIGH"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"}]}