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VulnerabilityPublished Updated

CVE-2026-58269: Sync-in server · Authentication Bypass Using an Alternate Path or Channel

Affects Sync-in serverSource CVE Database V5

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Not known to be exploited · CVSS 8.1 High : upgrade to 2.4.0 soon.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.4.0
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 21 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Upgrade server and sync-in/server to 2.4.0.

Affected software

ProductAffectedFixed in
Sync-inserverAffected
  • <2.4.0
Fixed in
  • 2.4.0
GitHubsync-in/serverpkg:github/sync-in/serverOther threatsAffected
  • <2.4.0
Fixed in
  • 2.4.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Sync-in Server to version 2.4.0 or later, where this authentication bypass vulnerability is patched. No other mitigation is required as the vendor has provided an official fix.

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.

References

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