{"id":"CVE-2026-58271","summary":"@sync-in/server vulnerable to TOTP Brute-Force via `POST /api/app/sync/register`","details":"Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, `POST /api/app/sync/register` accepts credentials and a TOTP code to register a desktop sync client. On a failed TOTP, `SyncClientsManager.register()` calls `updateAccesses(user, ip, false)`, which hits a freeze branch that writes `passwordAttempts` back unchanged. The counter never reaches `USER_MAX_PASSWORD_ATTEMPTS` (10) and the lockout gate never fires. A successful guess returns a `{clientId, clientToken}` pair. The token can be exchanged via `POST /api/app/sync/auth/cookie` for a full JWT. While the code is valid, the attacker can also call `POST /api/auth/2fa/disable` to permanently remove MFA. Version 2.4.0 patches the issue.","aliases":["GHSA-274f-6w77-8qm9"],"modified":"2026-09-22T11:45:43.812335895Z","published":"2026-09-21T19:50:14.539Z","database_specific":{"cwe_ids":["CWE-307"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58271.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58271.json"},{"type":"ADVISORY","url":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58271"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/sync-in/server","events":[{"introduced":"0"},{"fixed":"814d4e1f744fe709bdb4f5e9d4c6c6bd54982e09"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2.4.0"}],"source":"AFFECTED_FIELD"}}],"versions":["v2.3.0","v2.2.1","v2.2.0","v2.1.0","v2.0.0","v1.11.0","v1.10.1","v1.10.0","v1.9.6","v1.9.5","v1.9.4","v1.9.3","v1.9.2","v1.9.1","v1.9.0","v1.8.1","v1.8.0","v1.7.0","v1.6.1","v1.6.0","v1.5.2","v1.5.1","v1.5.0","v1.4.0","v1.3.9","v1.3.8","v1.3.7","v1.3.6","v1.3.5","v1.3.4","v1.3.3","v1.3.2","v1.3.1","v1.3.0","v1.2.2","v1.2.1","v1.2.0","v1.1.1","v1.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58271.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"}]}