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Hybrid Backup SyncApplication · Qnap

CVE-2024-53695

CRITICAL · 9.1 CVSS v3.1 Published 2025-03-07
Fix available
A fix is available. Upgrade to 25.1.4.952 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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 HBS 3 Hybrid Backup Sync. If exploited, the vulnerability could allow remote attackers to modify memory or crash processes. We have already fixed the vulnerability in the following version: HBS 3 Hybrid Backup Sync 25.1.4.952 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 QNAP HBS 3 Hybrid Backup Sync allows remote attackers to modify memory or crash processes due to insufficient bounds checking. This is a critical flaw (CVSS 9.1) that can be exploited remotely without authentication.

MitigationUpdate HBS 3 Hybrid Backup Sync to version 25.1.4.952 or later to remediate the 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
Hybrid Backup SyncApplication
Affected:>= 25.1.0.627, < 25.1.4.952

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 HBS 3 Hybrid Backup Sync is installed
    Access the QNAP NAS admin web interface, go to App Center, and look for Hybrid Backup Sync 3 in the installed applications list. Alternatively, run 'qpkg -i | grep -i hybrid' on the NAS command line.
    Affected if HBS 3 Hybrid Backup Sync is not found on the system, then the vulnerability does not apply.
  2. Locate the installed version number
    In the QNAP App Center, click on Hybrid Backup Sync 3 and view the version information displayed. From command line, run 'qpkg -i HybridBackupSync3' or check '/share/CACHEDEV1_DATA/.qpkg/HybridBackupSync3/HybridBackupSync3.ini' for version details.
    Affected if Cannot determine version - further investigation required.
  3. Compare version against affected range
    Note the installed version (for example, 25.1.x.x format). The affected range is version 25.1.0.627 or higher, but lower than 25.1.4.952. Check if your installed version falls within this range.
    Affected if Installed version is 25.1.0.627 or any 25.1.x version up to and including 25.1.4.951 - the system is affected by this vulnerability.
  4. Confirm the application is accessible over network
    Verify that HBS 3 Hybrid Backup Sync is running and accessible, as the vulnerability can be exploited remotely without authentication. Check if the service is active in the QNAP interface or via command line 'ps | grep -i hbs'.
    Affected if HBS 3 service is exposed to network and version falls in affected range - the vulnerability is potentially exploitable.

The system is affected if QNAP HBS 3 Hybrid Backup Sync is installed with a version between 25.1.0.627 and 25.1.4.951 inclusive, and the service is running and network-accessible.

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 25.1.4.952 or later
Fixed in 25.1.4.952
Interim mitigation

Update HBS 3 Hybrid Backup Sync to version 25.1.4.952 or later to remediate the vulnerability.

Recommended fix High confidence

HBS 3 Hybrid Backup Sync 25.1.4.952 or later

  1. Access the QNAP NAS admin interface and navigate to App Center or the HBS 3 Hybrid Backup Sync application
  2. Check the current installed version of HBS 3 Hybrid Backup Sync (should be >= 25.1.0.627 and < 25.1.4.952 to be vulnerable)
  3. Locate HBS 3 Hybrid Backup Sync in the available updates
  4. Update to HBS 3 Hybrid Backup Sync version 25.1.4.952 or later
  5. Verify the update was successful by checking the application version after installation
  6. Confirm the new version is >= 25.1.4.952

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Hybrid Backup Sync Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,360
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,176.

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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-2024-53695 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