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Qsync CentralApplication · Qnap

CVE-2025-48723

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 in Qsync Central allows authenticated remote attackers to modify memory or crash processes. Exploitation requires prior compromise of a valid user account, indicating this is a post-authentication vulnerability.

MitigationUpgrade Qsync Central to version 5.0.0.4 or later. Until then, minimize exposure to untrusted networks, enforce strong credential policies, and monitor for suspicious account 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. Identify installed Qsync Central version
    Access the QTS desktop, open App Center, locate Qsync Central, and note the version number displayed. Alternatively, log into the QNAP device via SSH and run: cat /share/CACHEDEV1_DATA/.qpkg/QSyncCenter/.qpkg_version 2>/dev/null || cat /mnt/ext/opt/qnap_qsync/VERSION 2>/dev/null
    Affected if The version shown is 5.0.0.0, 5.0.0.1, 5.0.0.2, or 5.0.0.3 (any version >= 5.0.0.0 but < 5.0.0.4)
  2. Verify Qsync Central service is running
    Log into QTS, go to Control Panel > Services > Qsync Central, or check via SSH with: ps aux | grep -i qsync
    Affected if Qsync Central service is actively running and accepting connections
  3. Confirm user authentication is enabled for Qsync
    Open Qsync Central web interface, navigate to Settings > Authentication, or check via: getcfg QsyncService Enable_Auth
    Affected if User authentication is enabled, as the vulnerability requires valid credentials to exploit
  4. Assess network accessibility of Qsync Central
    Check if port 8080 or the Qsync Central web interface is exposed externally. In QTS, go to Control Panel > Network & Virtual Switch > Port Forwarding, or run: netstat -tlnp | grep -E '8080|qsync'
    Affected if Qsync Central is reachable from untrusted networks, increasing exposure to remote attackers

Your environment is affected if Qsync Central version is 5.0.0.0 through 5.0.0.3, the service is running, and valid user credentials exist in the system, as the buffer overflow requires authenticated access to trigger memory corruption.

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 or later. Until then, minimize exposure to untrusted networks, enforce strong credential policies, and monitor for suspicious account activity.

Recommended fix High confidence

Qsync Central 5.0.0.4

  1. Log into QNAP NAS as administrator
  2. Open App Center or Qsync Central settings
  3. Check current Qsync Central version (should be < 5.0.0.4)
  4. Update Qsync Central to version 5.0.0.4 or later via QNAP App Center
  5. Verify the update was successful and the new version is 5.0.0.4 or higher
  6. Restart Qsync Central service if not automatically restarted

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
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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-2025-48723 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