Cyber Resilience

CVE-2025-62842

Path Traversal in Qnap Hybrid Backup Sync ≤ 26.2.0.938

Published
02 January 2026
Modified
25 July 2026
Patch / advisory
CVSS Score v4 7.0
Click a component to see what it means
Raw vectorCVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0023 14th percentile
Risk Priority 25 floored blend · peak EPSS

Summary

CVE-2025-62842 is a high-severity External Control of File Name or Path (CWE-73) vulnerability in Qnap Hybrid Backup Sync. Its CVSS base score is 7.0 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-62842 is an external control of file name or path vulnerability (CWE-73) affecting HBS 3 Hybrid Backup Sync. Published on 2026-01-02, it has a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high impact on confidentiality, integrity, and availability with low attack complexity and privileges required.

An attacker with local network access and low privileges on the affected system can exploit this vulnerability to read or modify arbitrary files or directories, potentially leading to significant data compromise or system disruption.

QNAP's security advisory (QSA-25-46) states that the vulnerability has been fixed in HBS 3 Hybrid Backup Sync version 26.2.0.938 and later; users should update to a patched version for mitigation. Full details are available at https://www.qnap.com/en/security-advisory/qsa-25-46.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

An external control of file name or path vulnerability has been reported to affect HBS 3 Hybrid Backup Sync. If an attacker gains local network access, they can then exploit the vulnerability to read or modify files or directories. We…

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have already fixed the vulnerability in the following version: HBS 3 Hybrid Backup Sync 26.2.0.938 and later

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
T1083 File and Directory Discovery Discovery
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1574.007 Path Interception by PATH Environment Variable Stealth
Adversaries may execute their own malicious payloads by hijacking environment variables used to load libraries.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-53695Same product: Qnap Hybrid Backup Sync
CVE-2024-50388Same product: Qnap Hybrid Backup Sync
CVE-2025-62840Same product: Qnap Hybrid Backup Sync
CVE-2025-54162Same product class: NAS / storage appliance
CVE-2021-28799Same product: Qnap Hybrid Backup Sync
CVE-2022-27593Same product class: NAS / storage appliance
CVE-2024-47265Same product class: NAS / storage appliance
CVE-2025-58467Same product class: NAS / storage appliance
CVE-2025-58463Same product class: NAS / storage appliance
CVE-2025-58464Same product class: NAS / storage appliance

Affected Assets

qnap
hybrid backup sync
≤ 26.2.0.938

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

Input validation directly rejects or sanitizes untrusted path strings before they reach filesystem operations.

Enforces authorization checks on the actual resource accessed, blocking unauthorized files even when a malicious path is supplied.

Least-privilege limits the set of files or directories any subject can affect, shrinking the blast radius of a path-control flaw.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 full match
prevents

Secure SDLC practices include input validation and path sanitization that eliminate this weakness.

PR.AA-05 mostly match
prevents

Least-privilege file authorization directly limits damage from externally controlled paths.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect path-traversal issues but does not itself implement preventive controls.

prevents

Secure development lifecycle mandates input validation and path-handling controls that directly prevent external file/path manipulation.

prevents

Application security requirements explicitly call for controls against untrusted input influencing file operations.

prevents

Secure architecture principles discourage unsafe path construction but do not prescribe concrete file-name controls.

prevents

Secure coding standards require canonicalization, allow-listing, and bounds checks on file paths, directly eliminating CWE-73.

mitigates

Information access restriction limits which files can be reached, indirectly reducing impact of path manipulation.

References