Qsync CentralApplication · Qnap

CVE-2025-57709

HIGH · 8.1 CVSS v3.1 Published 2026-02-11
Fix available
A fix is available. Upgrade to 5.0.0.4 or later.
See remediation →
87/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A buffer overflow vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: Qsync Central 5.0.0.4 ( 2026/01/20 ) and later

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Buffer overflow vulnerability in Qsync Central allowing an authenticated remote attacker to modify memory or crash processes via malformed input. The vulnerability requires prior account compromise to exploit.

MitigationUpgrade Qsync Central to version 5.0.0.4 or later. If immediate patching is not feasible, restrict network access to Qsync Central and ensure strong credential policies to prevent initial account compromise.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Qsync CentralApplication
Affected:>= 5.0.0.0, < 5.0.0.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Qsync Central is installed
    Access the QNAP admin console and navigate to App Center or check the system logs for Qsync Central package installation.
    Affected if Qsync Central is not installed on the QNAP device.
  2. Check Qsync Central version
    Open Qsync Central in the QNAP admin interface and locate the version number displayed in the application settings or about section.
    Affected if The installed version is 5.0.0.0, 5.0.0.1, 5.0.0.2, or 5.0.0.3 (any version >= 5.0.0.0 but < 5.0.0.4).
  3. Confirm Qsync Central service is running
    Check the QNAP services status page or use the QNAP CLI to verify Qsync Central process is active.
    Affected if Qsync Central is running and the version falls within the affected range.
  4. Assess remote access exposure
    Review network configuration to determine if Qsync Central is accessible from external networks or if port forwarding exposes it.
    Affected if Qsync Central is exposed to untrusted networks and the version is within the affected range.
  5. Verify authentication requirements
    Check that strong password policies and account security measures are in place for QNAP user accounts.
    Affected if Weak credentials exist and Qsync Central version is within the affected range.

A user is affected if Qsync Central version is 5.0.0.0 through 5.0.0.3 and the service is accessible, especially if account security is weak.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.0.0.4 or later
Fixed in 5.0.0.4
Interim mitigation

Upgrade Qsync Central to version 5.0.0.4 or later. If immediate patching is not feasible, restrict network access to Qsync Central and ensure strong credential policies to prevent initial account compromise.

Recommended fix High confidence

Qsync Central 5.0.0.4

  1. Identify the current Qsync Central version installed on the QNAP NAS
  2. Access the QNAP admin interface (QTS or QuTS hero)
  3. Navigate to the Qsync Central application settings
  4. Check for updates or install the update to Qsync Central version 5.0.0.4 or later
  5. Alternatively, download Qsync Central 5.0.0.4 from the official QNAP website and install via the App Center
  6. Verify the installed version is 5.0.0.4 or later

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Qsync Central Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-57709 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data