🛡️ CVE-2026-33976 — notesnook-desktop

🔴 CVSS 9.6 — Critical ⚠️ Exploit Public CWE-79 NVD
9.6
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Notesnook is a note-taking app. Prior to version 3.3.11 on Web/Desktop and 3.3.17 on Android/iOS, a stored XSS in the Web Clipper rendering flow can be escalated to remote code execution in the desktop app. The root cause is that the clipper preserves attacker-controlled attributes from the source page’s root element and stores them inside web-clip HTML. When the clip is later opened, Notesnook renders that HTML into a same-origin, unsandboxed iframe using contentDocument.write(...). Event-handler attributes such as onload, onclick, or onmouseover execute in the Notesnook origin. In the desktop app, this becomes RCE because Electron is configured with nodeIntegration: true and contextIsolation: false. Version 3.3.11 Web/Desktop and 3.3.17 on Android/iOS patch the issue.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-33976 is classified as CWE-79: Cross-site Scripting (XSS). User-supplied data is written into a page without escaping, so attacker script runs in the browser of anyone who views it.

Affected software

CVE-2026-33976 is recorded against 2 packages.

  • notesnook-desktop (fixed in 3.3.11)
  • notesnook-mobile (fixed in 3.3.17)

Timeline and source

Published on 27 March 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com

Details

Severity CRITICAL
CVSS Score 9.6
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CWE CWE-79
Public Exploit ⚠️ Yes
Source NVD
Published 2026-03-27
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
notesnook-desktop — 3.3.11
notesnook-mobile — 3.3.17

Similar Threats

Exploit Protection

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CVE-2026-33976 carries CVSS 9.6 Critical rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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