Vulnerability · Published Mar 27, 2026 · Assigned by GitHub_M
CVE-2026-33976Notesnook vulnerable to RCE via stored XSS in Web Clipper rendering
Critical 9.7
In plain English
A critical-severity cross-site scripting in Notesnook iOS/Android from streetwriters. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| streetwriters | Notesnook Web/Desktop | < 3.3.11 |
| streetwriters | Notesnook iOS/Android | < 3.3.17 |
Weakness: CWE-79, CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H