Qsync CentralApplication · Qnap

CVE-2025-52869

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

A buffer overflow vulnerability exists in Qsync Central that allows an authenticated remote attacker to modify memory or crash processes. The vulnerability can be exploited after the attacker gains a valid user account on the system.

MitigationUpgrade Qsync Central to version 5.0.0.4 (released 2026/01/20) or later to remediate this vulnerability. Until then, limit access to trusted users only and monitor for suspicious activity.

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
    On the QNAP NAS, check if Qsync Central is installed via the App Center or by examining running processes (look for qsync or qsnc processes).
    Affected if Qsync Central is not installed on the system, the CVE does not apply.
  2. Locate the installed version number
    Access Qsync Central via the QNAP admin interface (usually at https://[nas-ip]:[port]/qsync) and navigate to the Control Panel > Applications > Qsync Central, or use the QNAP CLI tool 'qpkg --info Qsync_Central' to retrieve the package version.
    Affected if Unable to determine the version means you cannot confirm if the vulnerability applies.
  3. Compare against affected versions
    Check if the installed version is 5.0.0.0, 5.0.0.1, 5.0.0.2, or 5.0.0.3. Any of these versions fall within the vulnerable range.
    Affected if Installed version is 5.0.0.0 through 5.0.0.3 inclusive.
  4. Confirm user account accessibility
    Review Qsync Central user accounts and authentication logs to determine if untrusted or compromised accounts could exist with access to the Qsync service.
    Affected if The vulnerability requires an authenticated attacker, so assess whether untrusted users could obtain valid credentials.

You are affected if Qsync Central version 5.0.0.0 through 5.0.0.3 is installed and untrusted or compromised user accounts could potentially authenticate to the service.

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 (released 2026/01/20) or later to remediate this vulnerability. Until then, limit access to trusted users only and monitor for suspicious activity.

Recommended fix High confidence

Qsync Central 5.0.0.4 and later

  1. Identify the current version of Qsync Central installed on the system
  2. If the installed version is >= 5.0.0.0 and < 5.0.0.4, initiate an upgrade to version 5.0.0.4 or later
  3. Follow QNAP's standard upgrade procedure for Qsync Central (typically via the QTS Control Center or QNAP software center)
  4. After upgrade, verify the version has been successfully updated to 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
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-52869 — 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-2025-52869 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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