{"id":"CVE-2024-39839","aliases":["BIT-mattermost-2024-39839","GHSA-vg6q-84p8-qvqh","GO-2024-3024"],"url":"https://o3.security/vulnerability/CVE-2024-39839","summary":"Remote username set to an arbitrary string by remote user","details":"Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before.","published":"2024-08-01T14:05:07.339Z","modified":"2026-08-12T03:51:11.776155018Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"9.5.7"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"9.7.6"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"9.8.2"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"9.9.1"}],"fix":null,"references":[{"type":"WEB","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/39xxx/CVE-2024-39839.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-39839"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost"},{"type":"WEB","url":"https://pkg.go.dev/vuln/GO-2024-3024"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:11.776155018Z"}}