Sync-in Server Updates Fix 2FA, ReDoS, and Login Enumeration Flaws
Tech GuruQuick Answer
The authority published GHSA-274f-6w77-8qm9 for @sync-in/server through 2.3.0, plus login-enumeration exposure through 2.4.0. The project disclosed a complete two-factor authentication bypass, a TOTP brute-force path, regular-expression denial of service, and residual username enumeration through login timing. Affected deployments should be matched to the authority's exact scope and moved to the supported fixed release.
Confirm Scope And Apply The Supported Fix
What to do now: Inventory @sync-in/server through 2.3.0, plus login-enumeration exposure through 2.4.0, match the exact affected release or feature, apply the authority-supported fixed build or service remediation, validate the dependent workflow, and preserve evidence.
Last verified: 2026-09-22 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | @sync-in/server through 2.3.0, plus login-enumeration exposure through 2.4.0 |
|---|---|
| Advisory | GHSA-274f-6w77-8qm9 / GHSA-92cr-jxw4-5wjg / GHSA-jx63-h26r-8cph / GHSA-29hq-23m2-2j47 |
| CVEs | CVE-2026-58269, CVE-2026-58270, CVE-2026-58271, CVE-2026-58272 |
| Authoritative release date | 2026-09-22 14:44:43 UTC |
| Authority revision date | 2026-09-22 14:49:27 UTC |
| Affected versions | @sync-in/server through 2.3.0 for the 2FA bypass, TOTP brute force, and ReDoS issues; versions through 2.4.0 for login timing enumeration. |
| Fixed version | @sync-in/server 2.4.1, which includes the 2.4.0 security corrections |
| CVSS base score | 5.3 / 6.5 / 6.8 / 8.1 (CVSS v3.1) |
| CVSS severity | Medium to High |
| Exploitation status | Not stated by the authority; no exploitation claim is inferred. |
What Changed
The project disclosed a complete two-factor authentication bypass, a TOTP brute-force path, regular-expression denial of service, and residual username enumeration through login timing.
What To Validate Now
- Inventory. Locate @sync-in/server through 2.3.0, plus login-enumeration exposure through 2.4.0 deployments, versions, enabled features, exposure paths, owners, and dependent services.
- Establish applicability. Compare each deployment with the authority's affected-version statement: @sync-in/server through 2.3.0 for the 2FA bypass, TOTP brute force, and ReDoS issues; versions through 2.4.0 for login timing enumeration. Do not infer applicability from product family or severity alone.
- Remediate. Apply @sync-in/server 2.4.1, which includes the 2.4.0 security corrections through the supported vendor or project channel, following the current advisory and change-control requirements.
- Validate. Confirm the resulting version or managed-service state, exercise representative functionality and recovery paths, monitor for regressions, and document exceptions.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
Use the exact supported release stream and repository. Test dependencies, clusters, integrations, and rollback before broad deployment; a CVSS rating or reachable feature is not evidence of exploitation.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
