CVE-2026-41161: Username Enumeration via Timing Attack

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-08 · updated 2026-10-26
Weakness: CWE-208

Description

Sync-in Server is a secure, open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.2.0, the /api/auth/login endpoint contains a logic flaw that allows unauthenticated remote attackers to enumerate valid usernames by measuring the application's response time. This issue has been patched in version 2.2.0.

Affected products

Sync-in server: before 2.2.0 — fixed in 2.2.0

How to fix

Upgrade to a fixed version: Sync-in server 2.2.0. Check the vendor advisory for mitigations.

References

https://github.com/Sync-in/server/releases/tag/v2.2.0
https://github.com/Sync-in/server/security/advisories/GHSA-43fj-qp3h-hrh5
https://github.com/Sync-in/server/security/advisories/GHSA-43fj-qp3h-hrh5

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