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CVE-2026-39991

Stored Cross-Site Scripting (XSS) in Note Station file upload functionality

CVSS score

4.8

EPSS probability

%0.5

Risk score

0.0

Published

17 h ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

CVE-2026-39991: Stored Cross-Site Scripting (XSS) Vulnerability in Notes Station 3

Sources read

2

Source agreement

Tam uyum

Evidence confidence

%63

Short explanation

A stored cross-site scripting (XSS) vulnerability has been reported in Notes Station 3 file upload functionality, allowing a remote attacker to inject malicious code after gaining a user account.

Why does it matter?

This vulnerability allows an attacker to inject malicious code within Notes Station 3 if they successfully obtain a user account.

What should be done?

  • Update to Notes Station 3 version 3.9.12 and later
  • Follow vendor advisories
Chain of evidence and sources2 verified claims

Notes Station 3 dosya yükleme işlevinde saklı Siteler Arası Kod Çalıştırma (XSS) zafiyeti bulunmaktadır.

S0 · daybreach-canonicalS1 · cvelist

Uzak bir saldırgan, kullanıcı hesabı elde ettikten sonra bu zafiyeti istismar ederek kötü amaçlı kod enjekte edebilir.

S0 · daybreach-canonicalS2 · nvd
Show the technical text from the sources

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 vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

CWE: CWE-79

Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-39991 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1QNAP Systems Inc.Notes Station 3 View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
4.8CVSS V40MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XNVD
4.8CVSS V4_0MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NCVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-39991 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-39991 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsLow
User—

Official Sources and Advisories

https://www.qnap.com/en/app-release-notes?keyword=Notes%20Station%203&app=NotesStation3&product-line=nasvendor-advisory

CVSS Vector Radar Chart

4.8 / 10
Attack VectorNetworkComplexityLowPrivilegesLowUser Interact.RequiredConfidentialityLowIntegrityNoneAvailabilityNone

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow privileges
User InteractionA
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)A
Availability (Erişilebilirlik)None

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

QS
QNAP Systems Inc. logo
QNAP Systems Inc.

Weakness Type (CWE & CAPEC)

CWE-79

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