{"api_version":"1","generated_at":"2026-09-23T00:05:09+00:00","cve":"CVE-2026-58271","urls":{"html":"https://cve.report/CVE-2026-58271","api":"https://cve.report/api/cve/CVE-2026-58271.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-58271","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-58271"},"summary":{"title":"@sync-in/server vulnerable to TOTP Brute-Force via `POST /api/app/sync/register`","description":"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.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-09-21 20:17:26","updated_at":"2026-09-21 20:17:26"},"problem_types":["CWE-307","CWE-307 CWE-307: Improper Restriction of Excessive Authentication Attempts"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"6.8","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","baseScore":6.8,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"6.8","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.8,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9","name":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58271","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58271","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Sync-in","product":"server","version":"affected < 2.4.0","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"server","vendor":"Sync-in","versions":[{"status":"affected","version":"< 2.4.0"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.8,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-307","description":"CWE-307: Improper Restriction of Excessive Authentication Attempts","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-21T19:50:14.539Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9"}],"source":{"advisory":"GHSA-274f-6w77-8qm9","discovery":"UNKNOWN"},"title":"@sync-in/server vulnerable to TOTP Brute-Force via `POST /api/app/sync/register`"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-58271","datePublished":"2026-09-21T19:50:14.539Z","dateReserved":"2026-06-29T21:54:30.332Z","dateUpdated":"2026-09-21T19:50:14.539Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-21 20:17:26","lastModifiedDate":"2026-09-21 20:17:26","problem_types":["CWE-307","CWE-307 CWE-307: Improper Restriction of Excessive Authentication Attempts"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","baseScore":6.8,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1.6,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"58271","Ordinal":"1","Title":"@sync-in/server vulnerable to TOTP Brute-Force via `POST /api/ap","CVE":"CVE-2026-58271","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"58271","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"@sync-in/server vulnerable to TOTP Brute-Force via `POST /api/ap"}]}}}