Qsync CentralApplication · Qnap

CVE-2025-30262

MEDIUM · 6.5 CVSS v3.1 Published 2025-08-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 5.0.0.0 ( 2025/06/13 ) 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 can be exploited by a remote attacker who has obtained a valid user account. The vulnerability leads to a denial-of-service condition when the NULL pointer is dereferenced during attack execution.

MitigationUpdate Qsync Central to version 5.0.0.0 or later. Additionally, enforce strong account security controls (MFA, strong passwords, account lockout policies) to make initial account compromise more difficult, as the attacker needs a valid user account to exploit this vulnerability.

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

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. Confirm Qsync Central installation
    Locate Qsync Central on the QNAP NAS - typically accessible via the App Center or by checking running services on the NAS management interface.
    Affected if Qsync Central is installed on the QNAP device.
  2. Identify installed Qsync Central version
    Access Qsync Central through the NAS web interface, then navigate to the settings or about section to view the software version number.
    Affected if The installed version is exactly 5.0.0.0.
  3. Verify remote access configuration
    Check Qsync Central settings to determine if remote synchronization or web-based access is enabled, which would allow remote attacker access.
    Affected if Remote access to Qsync Central is enabled and exposed to network.
  4. Review user account configuration
    Examine the user accounts configured in Qsync Central - check for any accounts that have sync permissions and could be targeted for credential theft.
    Affected if There are active user accounts with Qsync access, particularly if those accounts have weak credentials or no MFA protection.

You are affected only if Qsync Central version 5.0.0.0 is installed AND remote network access is available AND a valid user account exists that could be compromised by an attacker.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Qsync Central to version 5.0.0.0 or later. Additionally, enforce strong account security controls (MFA, strong passwords, account lockout policies) to make initial account compromise more difficult, as the attacker needs a valid user account to exploit this vulnerability.

Recommended fix Moderate confidence

Qsync Central 5.0.0.0 (2025/06/13) or later

  1. 1. Log into the QNAP NAS administration interface
  2. 2. Navigate to the Qsync Central application settings
  3. 3. Check the current installed version of Qsync Central
  4. 4. Download and install Qsync Central version 5.0.0.0 (released 2025/06/13) or later from the QNAP download center
  5. 5. Verify the installation by checking the updated version number in the Qsync Central settings
  6. 6. Restart the Qsync Central service if prompted to ensure the vulnerability is remediated

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
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Scan for this in your stack

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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-2025-30262 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