QNAP Hybrid Backup Sync: Use of hard-coded cryptographic key
Summary
QNAP HBS 3 Hybrid Backup Sync and Hybrid Backup Sync 26.4.x before the fixed releases contain a hard-coded cryptographic key. A remote attacker may be able to compromise the security of the system, and the CVSS vector indicates an adjacent network attack. The CVE record does not describe further conditions, and the NVD analysis is still pending.
Affected
- HBS 3 Hybrid Backup Sync 26.4.x before 26.4.0.521
- Hybrid Backup Sync 26.4.x before 26.4.1.563
- Lower bound of affected branches beyond 26.4.x: Unknown.
Fixed in
- HBS 3 Hybrid Backup Sync 26.4.0.521 and later
- Hybrid Backup Sync 26.4.0.521 and later
- Hybrid Backup Sync 26.4.1.563 and later
Workaround
- Unknown. No vendor workaround is documented; upgrading is the only documented remedy.
Exploitation
- No evidence of exploitation in the wild or public proof-of-concept code found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- VulDB lists the status as "0-Day" without explanation; treat as unclear.
Our recommendation
- Inventory QNAP NAS devices running HBS and check their versions.
- Upgrade to the fixed releases listed above and verify the branch against the QNAP release notes.
- Keep NAS management and backup services off the internet and restrict them to trusted networks.
- Check the NVD and QNAP advisory pages again once the analysis is published.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- QNAP App Release Notes (HBS 3) www.qnap.com
- QNAP App Release Notes (Hybrid Backup Sync) www.qnap.com
- VulDB entry 428325 vuldb.com
- CVE record mirror (threatint) cve.threatint.com
- OffSeq radar CVE-2025-62841 radar.offseq.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 23:43.
Original description (NVD)
An use of hard-coded cryptographic key vulnerability has been reported to affect HBS 3 Hybrid Backup Sync and Hybrid Backup Sync. If exploited, the vulnerability could allow remote attackers to compromise the security of the system. We have already fixed the vulnerability in the following version: HBS 3 Hybrid Backup Sync 26.4.0.521 and later Hybrid Backup Sync 26.4.0.521 and later Hybrid Backup Sync 26.4.1.563 and later
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
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