{"id":"CVE-2026-58271","title":"Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing","summary":"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 TOT…","severity":"medium","cvss":6.8,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-307"],"vendor":"Sync-in","product":"server","affected":["server < 2.4.0"],"patched":["@sync-in/server 2.4.0"],"published":"2026-09-21","updated":"2026-09-24","sourceUpdated":"2026-09-24T23:17:12.723","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-58271","references":[{"url":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9","label":"security-advisories@github.com"},{"url":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58271"},{"url":"https://github.com/Sync-in/server/pull/228"},{"url":"https://github.com/Sync-in/server/commit/b13a4aad5c2b38fe8231a0d007cd08a086ec5bdb"},{"url":"https://github.com/Sync-in/server/releases/tag/v2.4.0"},{"url":"https://github.com/advisories/GHSA-274f-6w77-8qm9"}],"tags":["nvd","cve.org","exploit-available","ghsa","npm"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-24T22:35:57.537707Z"},"epss":0.00219,"epssPercentile":0.12328,"aliases":["GHSA-274f-6w77-8qm9"],"ecosystem":"npm","ingestedAt":"2026-09-21T19:51:58.865Z","slug":"CVE-2026-58271","body":"## Overview\n\nSync-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-58271)\n\nAffected packages:\n\n- `@sync-in/server <= 2.3.0`\n\nPatched in:\n\n- `@sync-in/server 2.4.0`\n\nSource: https://github.com/advisories/GHSA-274f-6w77-8qm9","depth":"twilight","depthScore":49,"depthScoreParts":{"impact":37.4,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":210435,"id":"CVE-2026-58271","ts":1790290513062,"field":"exploit_available","old":"false","new":"true"}]}