Qsync CentralApplication · Qnap

CVE-2025-33034

MEDIUM · 6.5 CVSS v3.1 Published 2025-10-03
Fix available
A fix is available. Upgrade to 5.0.0.1 or later.
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 path traversal vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to read the contents of unexpected files or system data. 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 confidence

A path traversal vulnerability in Qsync Central allows an authenticated remote attacker to access arbitrary files on the system by using traversal sequences (e.g., ../../../') in file paths, potentially exposing sensitive system data beyond the intended sync directories.

MitigationUpgrade Qsync Central to version 5.0.0.1 or later. Until patched, restrict network access to the Qsync Central interface and enforce strong user authentication to reduce the risk of credential compromise.

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:>= 4.2.0.0, < 5.0.0.1

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
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 if Qsync Central is installed
    On the QNAP NAS, check for Qsync Central application via the App Center or by looking for the qsync process in running processes. The web interface typically runs on port 8080 or 443.
    Affected if Qsync Central is installed and running on the system
  2. Determine the installed Qsync Central version
    Access the Qsync Central admin interface and navigate to the Control Panel or About section to view the software version. Alternatively, check the installed package information via QNAP's command line if available.
    Affected if The installed version falls within the range >= 4.2.0.0 and < 5.0.0.1
  3. Verify the Qsync Central web interface is network accessible
    Check if the Qsync Central web portal (typically accessed via the NAS IP or myqnapcloud link on port 8080/443) is reachable from network locations. Confirm whether firewall rules allow external access.
    Affected if The Qsync Central web interface is exposed to network-accessible IPs beyond the local administrative network
  4. Confirm user authentication is configured
    Review the Qsync Central user management settings to verify that user accounts exist and authentication is required for access. The vulnerability requires valid credentials to exploit.
    Affected if Valid user accounts are configured for Qsync Central access (authentication is required for exploitation)

You are affected if Qsync Central is installed with a version between 4.2.0.0 and 5.0.0.1 (exclusive), the web interface is network-accessible, and user authentication is configured.

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 5.0.0.1 or later
Fixed in 5.0.0.1
Interim mitigation

Upgrade Qsync Central to version 5.0.0.1 or later. Until patched, restrict network access to the Qsync Central interface and enforce strong user authentication to reduce the risk of credential compromise.

Recommended fix High confidence

Qsync Central 5.0.0.1

  1. Log in to the QNAP NAS admin interface
  2. Navigate to Qsync Central application management
  3. Check current installed version to confirm it is between 4.2.0.0 and 5.0.0.0
  4. Download Qsync Central version 5.0.0.1 or later from the official QNAP download center
  5. Apply the update through the QNAP App Center or firmware update mechanism
  6. Verify the installed version shows 5.0.0.1 or later after update

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
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,570
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,512.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-33034 — 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-2025-33034 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