Vulnerability Description
Notesnook is a note-taking app focused on user privacy & ease of use. Prior to Notesnook Web/Desktop version 3.3.15 and prior to Notesnook iOS/Android version 3.3.20, a stored XSS vulnerability in the note export flow can be escalated to remote code execution in the desktop app. The root cause is that exported note fields such as title, headline, and content are inserted into the generated HTML template without HTML escaping. When the note is later exported to PDF, Notesnook renders that HTML into a same-origin, unsandboxed iframe using iframe.srcdoc = .... Injected script executes in the Notesnook origin. In the desktop app, this becomes RCE because Electron is configured with nodeIntegration: true and contextIsolation: false. This issue has been patched in Notesnook Web/Desktop version 3.3.15 and Notesnook iOS/Android version 3.3.20.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Streetwriters | Notesnook Desktop | < 3.3.15 |
| Streetwriters | Notesnook Mobile | < 3.3.20 |
Related Weaknesses (CWE)
References
- https://github.com/streetwriters/notesnook/releases/tag/3.3.20-androidRelease Notes
- https://github.com/streetwriters/notesnook/releases/tag/v3.3.15Release Notes
- https://github.com/streetwriters/notesnook/security/advisories/GHSA-fjm8-jg78-89Vendor Advisory
FAQ
What is CVE-2026-42090?
CVE-2026-42090 is a vulnerability with a CVSS score of 9.6 (CRITICAL). Notesnook is a note-taking app focused on user privacy & ease of use. Prior to Notesnook Web/Desktop version 3.3.15 and prior to Notesnook iOS/Android version 3.3.20, a stored XSS vulnerability in the...
How severe is CVE-2026-42090?
CVE-2026-42090 has been rated CRITICAL with a CVSS base score of 9.6/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-42090?
Check the references section above for vendor advisories and patch information. Affected products include: Streetwriters Notesnook Desktop, Streetwriters Notesnook Mobile.