Read the docs
TI-2026-74709 Aliases CVE-2026-39991

Stored cross-site scripting in QNAP Notes Station 3 file upload

Priority LOW 22CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

QNAP Notes Station 3 versions from 3.9.x before 3.9.12 contain a cross-site scripting flaw (CWE-79) in the file upload functionality, where input is not neutralized before it is placed in a web page. A remote attacker who has gained a user account can inject malicious code that runs in the browser of other users, with user interaction required.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

A cross-site scripting (XSS) vulnerability has been reported to affect Notes Station 3. If a remote attacker gains a user account, they can then exploit the vulnerability to inject malicious code. We have already fixed the vulnerability in the following version: Notes Station 3 3.9.12 and later

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00293 22nd percentileScored 2026-11-07
Fix Fixed Notes Station 3 (QNAP Systems Inc.): 3.9.12

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
QNAPNotes Station 33.9.x to before 3.9.123.9.12Patch availableCNA
  • Notes Station 3 VendorQNAP Affected 3.9.x to before 3.9.12 Fixed in 3.9.12 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:qnap:notes_station_3:*:*:*:*:*:*:*:*——QNAP
  • cpe:2.3:a:qnap:notes_station_3:*:*:*:*:*:*:*:* Versions — — ·QNAP

Remediation

Update QNAP Notes Station 3 to version 3.9.12 or later.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Notes Station 3 (QNAP Systems Inc.) Fixed in 3.9.12

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-39991

References

Other 1

  • TI-2022-10581 DeadBolt Ransomware KEVCVSS 3.1CRITICAL 10.0
  • TI-2021-09791 Improper Authorization Vulnerability in HBS 3 (Hybrid Backup Sync) KEVCVSS 3.1CRITICAL 10.0
  • TI-2020-02221 Command Injection Vulnerability in QTS and QuTS hero KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05103 Path traversal in QNAP NAS devices running Photo Station KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05102 Path traversal in QNAP NAS devices running Photo Station KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05101 Improper input validation in QNAP NAS devices KEVCVSS 3.1CRITICAL 9.8
See all 681 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences