{"id":"CVE-2017-18906","aliases":["GHSA-fpcr-4rr5-hpcp","GO-2026-4477"],"url":"https://o3.security/vulnerability/CVE-2017-18906","summary":"Mattermost Server vulnerable to user account takeover when Single Sign-On OAuth2 is used","details":"An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2, when Single Sign-On OAuth2 is used. An attacker could claim somebody else's account.","published":"2020-06-19T20:15:12.147Z","modified":"2026-07-31T18:30:16.818611512Z","cvss":{"score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","fixedVersion":"3.9.2-0.20170714134023-b17fca0d5ee7"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","fixedVersion":"3.10.2"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://mattermost.com/security-updates/"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-31T18:30:16.818611512Z"}}