CVE-2025-44009
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 · uneditedA 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 confidenceA NULL pointer dereference vulnerability in Qsync Central allows an authenticated remote attacker to crash the application, causing a denial-of-service condition. The vulnerability is triggered when the attacker, having gained a valid user account, exploits improper NULL pointer handling in the application's code path.
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>= 4.2.0.0, < 5.0.0.1CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Confirm Qsync Central is installedLocate Qsync Central application on the QNAP NAS via the App Center or by checking for the Qsync Central service process.Affected if Qsync Central is not installed on the system.
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Identify installed Qsync Central versionCheck the installed version of Qsync Central through the QNAP App Center interface or by querying the package management system.Affected if The installed version cannot be determined or is not visible.
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Compare version to affected rangeCompare the identified version against the affected range: versions >= 4.2.0.0 and < 5.0.0.1.Affected if The installed version falls within >= 4.2.0.0 and < 5.0.0.1.
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Verify user authentication is enabledCheck if user authentication for Qsync Central is enabled and if valid user accounts exist on the NAS.Affected if User authentication is enabled and valid user accounts are present, allowing an authenticated attacker to trigger the vulnerability.
The environment is affected if Qsync Central is installed with a version >= 4.2.0.0 and < 5.0.0.1, and user authentication is enabled, permitting authenticated users to trigger the NULL pointer dereference.
Generated from the published advisory. Verify against your own configuration.
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 · scoped5.0.0.1
Upgrade Qsync Central to version 5.0.0.1 or later. As a temporary measure until upgrade, restrict user account creation and monitor for anomalous authentication patterns.
Qsync Central 5.0.0.1 or later
- 1. Identify the current Qsync Central version by accessing the QNAP admin interface and checking System Settings > Qsync Central
- 2. Back up the Qsync Central configuration and any critical data according to QNAP backup best practices
- 3. Download Qsync Central version 5.0.0.1 or later from the official QNAP download center (www.qnap.com)
- 4. Apply the update through the QNAP admin interface: go to App Center > Qsync Central > Update, or use the manual upload option if available
- 5. Restart the Qsync Central service if not automatically done by the update process
- 6. Verify the new version is 5.0.0.1 or later in System Settings > Qsync Central
- 7. Test Qsync functionality to ensure normal operations are restored
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-44009 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-44009 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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