Qsync CentralApplication · Qnap

CVE-2025-52868

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 · moderate confidence

Buffer overflow vulnerability in Qsync Central allowing an authenticated remote attacker to modify memory or crash processes. The vulnerability stems from insufficient bounds checking in the affected component, enabling memory corruption when processing specific inputs.

MitigationUpgrade to Qsync Central version 5.0.0.4 or later. Since exploitation requires a valid user account, enforce strong password policies and implement network segmentation to limit exposure to unauthenticated attackers.

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
    Locate Qsync Central on the QNAP system through the App Center or by checking for the qsync process/service running on the device
    Affected if Qsync Central is not installed on the system, the vulnerability does not apply
  2. Identify the installed version of Qsync Central
    Access Qsync Central through the QNAP admin interface, go to the version information section, or use the QNAP CLI tools to query the package version
    Affected if The version cannot be determined or the software is not present
  3. Compare the installed version against the affected range
    Check if the installed version falls within >= 5.0.0.0 and < 5.0.0.4. Versions 5.0.0.0, 5.0.0.1, 5.0.0.2, and 5.0.0.3 are affected
    Affected if The installed version is 5.0.0.0, 5.0.0.1, 5.0.0.2, or 5.0.0.3, meaning the system is vulnerable
  4. Confirm remote access to Qsync Central is enabled
    Verify that Qsync Central is accessible over the network to remote users, as exploitation requires an authenticated remote attacker with a valid user account
    Affected if Remote access to Qsync Central is exposed to untrusted networks and user authentication is enabled

The environment is affected if Qsync Central version 5.0.0.0 through 5.0.0.3 is installed and the service is accessible to remote authenticated users.

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 to Qsync Central version 5.0.0.4 or later. Since exploitation requires a valid user account, enforce strong password policies and implement network segmentation to limit exposure to unauthenticated attackers.

Recommended fix High confidence

Qsync Central 5.0.0.4

  1. Log in to the QNAP NAS web interface with administrator credentials
  2. Navigate to the Qsync Central application
  3. Access the Control Panel or Settings for Qsync Central
  4. Check the current version (should be >= 5.0.0.0 and < 5.0.0.4)
  5. Locate the firmware/update option within Qsync Central settings
  6. Apply the update to Qsync Central version 5.0.0.4 or later
  7. Verify the installed version after update completion

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
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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-2025-52868 in production — separate from our analysis above.

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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