Qsync CentralApplication · Qnap

CVE-2025-44011

MEDIUM · 6.5 CVSS v3.1 Published 2025-10-03
Fix available
A fix is available. Upgrade to 5.0.0.1 or later.
See remediation →
71/100
Remediation priority · Elevated
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 NULL pointer dereference vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to launch a denial-of-service (DoS) attack. We have already fixed the vulnerability in the following version: Qsync Central 5.0.0.1 ( 2025/07/09 ) 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 · moderate confidence

A NULL pointer dereference vulnerability exists in Qsync Central that allows an authenticated remote attacker to crash the service, causing a denial-of-service condition. The attacker must first obtain valid user credentials before exploiting the NULL pointer dereference to trigger the crash.

MitigationUpgrade Qsync Central to version 5.0.0.1 or later. Until the update can be applied, enforce strict access controls and monitor for unauthorized account creation to reduce the attack surface.

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:>= 4.2.0.0, < 5.0.0.1

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
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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. Identify Qsync Central version
    Access the QNAP admin console and navigate to the Qsync Central application. Locate the version information typically displayed in the application settings or about section. Alternatively, check the QNAP App Center for the installed Qsync Central version.
    Affected if The installed version is 4.2.0.0 or higher but below 5.0.0.1
  2. Confirm Qsync Central service is running
    Log into the QNAP NAS web interface and verify the Qsync Central service status. Check if the service is started and running.
    Affected if Qsync Central is actively running and accessible on the network
  3. Determine if remote access is enabled
    Review the Qsync Central network settings to see if remote access or the web-based management interface is exposed beyond the local network. Check firewall rules and access permissions for the Qsync Central ports.
    Affected if Remote network access to Qsync Central is permitted
  4. Audit valid user accounts
    Review the list of users who have credentials configured for Qsync Central access. Check user permissions and whether demo or default accounts exist.
    Affected if There are valid user accounts configured that could be used by an attacker to authenticate

You are affected if Qsync Central version 4.2.0.0 through 5.0.0.0 is running and accessible to an attacker who possesses valid credentials.

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 5.0.0.1 or later
Fixed in 5.0.0.1
Interim mitigation

Upgrade Qsync Central to version 5.0.0.1 or later. Until the update can be applied, enforce strict access controls and monitor for unauthorized account creation to reduce the attack surface.

Recommended fix High confidence

Qsync Central 5.0.0.1

  1. Identify the current version of Qsync Central installed on the system
  2. Back up any critical data and configuration files for Qsync Central
  3. Download Qsync Central version 5.0.0.1 or later from the official QNAP download center
  4. Follow QNAP's standard upgrade procedure to install the new version
  5. Verify the upgrade was successful by checking the Qsync Central version

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

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-44011 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2025-44011 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