CVE-2026-58269 Sync-in Server has a complete 2FA Bypass via `POST /api/auth/token`
Attackers with stolen credentials can bypass Two-Factor Authentication on Sync-in Server by using the token endpoint, leading to account takeover.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-58269?
CVE-2026-58269 is a high-severity authentication bypass vulnerability in Sync-in server, published on 21 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, `POST /api/auth/token` authenticates with username and password only, then calls `getTokens()`, which returns full access and refresh JWTs without checking whether the account has TOTP 2FA enabled. An attacker with stolen or phished credentials can bypass 2FA in a single request. The parallel login endpoint (`POST /api/auth/login`) correctly enforces 2FA by calling `setCookies(user, res, true)`, which gates on `user.twoFaEnabled`. Version 2.4.0 patches the issue.
Weakness: CWE-288
Which versions are affected by CVE-2026-58269?
2 open source packages ship an affected version, including @sync-in/server.
| Package | Affected | Fixed in |
|---|---|---|
@sync-in/server npm | All versions | 2.4.0 |
@sync-in/server npm | All versions | 2.4.0 |
How do I fix CVE-2026-58269?
Upgrade @sync-in/server to 2.4.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-58269 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58269 exists.
Sources
Also known as GHSA-92cr-jxw4-5wjg.