CVE-2025-62842

Code execution via unvalidated file path

Published Jan 2, 2026 · Updated Jan 2, 2026

External path control in QNAP HBS 3 Hybrid Backup Sync before 26.2.0.938 allows remote attackers to execute code via a crafted file path. The write_file_to_svr method uses a user-supplied path in file operations without proper validation, enabling files accessible to the RR2 administrator to be read or modified. Attackers need local-network reachability; the method requires authentication, but its existing authentication mechanism can be bypassed.

CVSS severity7.0
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

External path control in QNAP HBS 3 Hybrid Backup Sync before 26.2.0.938 allows remote attackers to execute code via a crafted file path. The write_file_to_svr method uses a user-supplied path in file operations without proper validation, enabling files accessible to the RR2 administrator to be read or modified. Attackers need local-network reachability; the method requires authentication, but its existing authentication mechanism can be bypassed.

The record

CVE
CVE-2025-62842
Published
Jan 2, 2026
Updated
Jan 2, 2026
Vendor
Linn Products Limited
Product
Hybrid Backup Sync
Classifications
CWE-73, CAPEC-76, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=26.1.x <26.2.0.938

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Linn Products Limited · Hybrid Backup Syncversion=26.1.x <26.2.0.938

Published CVSS scores

7.0QNAP Systems Inc.CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-73External Control of File Name or Path
CAPEC-76Manipulating Web Input to File System Calls
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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