CVE-2026-39991
Received Received - Intake

Reflected XSS in QNAP Notes Station 3

Publication date: 2026-10-15

Last updated on: 2026-10-15

Assigner: QNAP Systems, Inc.

Description
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

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Meta Information

Published
2026-10-15
Last Modified
2026-10-15
Generated
2026-10-15
AI Q&A
2026-10-15
EPSS Evaluated
N/A
NVD
CVE-2026-39991
EUVD
EUVD-2026-101986

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
QNAP Systems Inc. Notes Station 3 3.9.x

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This is a cross-site scripting (XSS) vulnerability in Notes Station 3. If an attacker gains access to a user account, they can inject malicious code into the application. This could allow them to execute arbitrary scripts in the context of other users' sessions.

Detection Guidance

Detection requires checking the installed version of Notes Station 3. If the version is earlier than 3.9.12, the system is vulnerable. No specific commands are provided in the context.

Impact Analysis

An attacker could steal sensitive information like session cookies or credentials, perform actions on behalf of users, or deface the application. This could lead to unauthorized data access or loss of trust in the application.

Compliance Impact

This vulnerability could lead to unauthorized access to personal or sensitive data, violating GDPR and HIPAA requirements for data protection and confidentiality. Organizations may face compliance penalties if exploited.

Mitigation Strategies

Upgrade Notes Station 3 to version 3.9.12 or later to resolve the vulnerability. Ensure user accounts are secure to prevent unauthorized access.

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