4.8

CVE-2026-39991: qnap systems inc. notes station 3 Cross-site Scripting

CVSS: 4.8v4.0MediumAwaiting analysis
Published 15-10-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-39991 is a medium (CVSS 4.8) Cross-site Scripting vulnerability in qnap systems inc. notes station 3. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.5% of scored vulnerabilities.

Overall risk
19/100
0100
Low · default modelHow is this calculated?
CVSS score
4.8/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.29%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 15-10-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

21%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

15-10-202620-10-2026
EPSS score
0.29%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Qnap systems inc.1 product

1 vendor · 1 product

References

1 links