CVE-2026-33955
Received Received - Intake
Stored XSS in Notesnook Note Viewer Enables Remote Code Execution

Publication date: 2026-03-27

Last updated on: 2026-04-02

Assigner: GitHub, Inc.

Description
Notesnook is a note-taking app. Prior to version 3.3.11 on Web/Desktop, a cross-site scripting vulnerability stored in the note history comparison viewer can escalate to remote code execution in a desktop application. The issue is triggered when an attacker-controlled note header is displayed using `dangerouslySetInnerHTML` without secure handling. When combined with the full backup and restore feature in the desktop application, this becomes remote code execution because Electron is configured with `nodeIntegration: true` and `contextIsolation: false`. Version 3.3.11 patches the issue.
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Meta Information
Published
2026-03-27
Last Modified
2026-04-02
Generated
2026-06-16
AI Q&A
2026-03-28
EPSS Evaluated
2026-06-15
NVD
CVE-2026-33955
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
streetwriters notesnook_desktop to 3.3.11 (exc)
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.
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
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Executive Summary

This vulnerability exists in Notesnook, a note-taking app, prior to version 3.3.11 on Web/Desktop. It is a cross-site scripting (XSS) vulnerability located in the note history comparison viewer. The issue arises because an attacker-controlled note header is displayed using `dangerouslySetInnerHTML` without proper secure handling. This vulnerability can escalate to remote code execution in the desktop application when combined with the full backup and restore feature, due to Electron being configured with `nodeIntegration: true` and `contextIsolation: false`.

Mitigation Strategies

To mitigate this vulnerability, you should update Notesnook to version 3.3.11 or later, where the issue has been patched.

Avoid using vulnerable versions of the application, especially those prior to 3.3.11 on Web/Desktop.

Impact Analysis

The vulnerability can allow an attacker to execute arbitrary code remotely on the desktop application. This means that if an attacker controls the note header content, they can exploit the XSS vulnerability to run malicious code on the victim's machine. This can lead to full compromise of the desktop application, potentially allowing access to sensitive data, unauthorized actions, or further system compromise.

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