{"id":"CVE-2021-37859","aliases":["EUVD-2021-24338","GHSA-r4f6-w245-8wv4"],"status":"published","title":"Reflected XSS in OAuth Flow","description":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.","severity":{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.03288,"percentile":0.88578,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2021-08-05T19:40:10Z","modified":"2026-10-24T10:30:55Z","products":[{"vendor":"mattermost","product":"mattermost"}],"references":[{"url":"https://mattermost.com/security-updates/","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-37859"},{"url":"https://github.com/advisories/GHSA-r4f6-w245-8wv4"}],"sources":{"cve":[{"id":"CVE-2021-37859","title":"Reflected XSS in OAuth Flow","description":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.","status":"published","published":"2021-08-05T19:40:10Z","modified":"2024-08-04T01:30:09.121Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:32:58.028461Z"}],"euvd":[{"id":"EUVD-2021-24338","description":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.","status":"published","published":"2021-08-05T19:40:10Z","modified":"2024-08-04T01:30:09Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L","level":"high"}],"updated_at":"2026-11-03T03:24:26.118239Z"}],"ghsa":[{"id":"GHSA-r4f6-w245-8wv4","title":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled...","description":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.","status":"published","published":"2022-05-24T19:10:09Z","modified":"2023-01-30T05:01:16Z","cwes":["CWE-79"],"updated_at":"2026-11-02T14:46:22.480874Z"}],"nvd":[{"id":"CVE-2021-37859","description":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.","status":"published","published":"2021-08-05T20:15:09.533Z","modified":"2026-06-17T04:01:12.623Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L","level":"high","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:06:56.562207Z"}],"osv":[{"id":"CVE-2021-37859","description":"Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.","status":"published","published":"2021-08-05T20:15:09.533Z","modified":"2026-10-24T10:30:55.58789036Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:20.434873Z"}]}}