CVE-2026-39991: CWE-79 in QNAP Systems Inc. Notes Station 3
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
CVSS v4.0
Score 4.8medium
Affected software
QNAP Systems Inc.
Notes Station 3
pkg:github/qnap/notes-station-3Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-39991 is a CWE-79 cross-site scripting vulnerability affecting Notes Station 3 by QNAP Systems Inc. An attacker who has obtained a user account can exploit this vulnerability to inject malicious scripts. The vulnerability is present in versions starting from 3.9.x up to but not including 3.9.12. The vendor has released a fix in version 3.9.12 to address this issue.
Potential Impact
An attacker with a user account can exploit this XSS vulnerability to inject malicious code, potentially leading to script execution in the context of the victim user. The CVSS 4.8 (medium severity) reflects the moderate risk due to the requirement of user privileges and user interaction.
Mitigation Recommendations
Upgrade Notes Station 3 to version 3.9.12 or later, where the vulnerability has been fixed. Applying this official fix fully mitigates the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- qnap
- Date Reserved
- 2026-04-08T02:30:26.921Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ad0a18d2cdf04f65621d7ab
Added to database: 10/15/2026, 09:49:01 UTC
Last enriched: 10/15/2026, 10:04:00 UTC
Last updated: 10/15/2026, 19:00:27 UTC
Views: 16
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