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TI-2026-26317 Aliases CVE-2026-33976

Notesnook vulnerable to RCE via stored XSS in Web Clipper rendering

Priority HIGH 76CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting, Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79 and CWE-94.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00719 54th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Notesnook Web/Desktop (streetwriters): 3.3.11Notesnook iOS/Android (streetwriters): 3.3.17

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
streetwritersNotesnook Web/Desktopbefore 3.3.113.3.11Patch availableCNA
streetwritersNotesnook iOS/Androidbefore 3.3.173.3.17Patch availableCNA
  • Notesnook Web/Desktop Vendorstreetwriters Affected before 3.3.11 Fixed in 3.3.11 Patch available CNA
  • Notesnook iOS/Android Vendorstreetwriters Affected before 3.3.17 Fixed in 3.3.17 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:streetwriters:notesnook_desktop:*:*:*:*:*:*:*:*before 3.3.11Vulnerablestreetwriters
cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:android:*:*before 3.3.17Vulnerablestreetwriters
cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:iphone_os:*:*before 3.3.17Vulnerablestreetwriters
  • cpe:2.3:a:streetwriters:notesnook_desktop:*:*:*:*:*:*:*:* Versions before 3.3.11 Vulnerable ·streetwriters
  • cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:android:*:* Versions before 3.3.17 Vulnerable ·streetwriters
  • cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:iphone_os:*:* Versions before 3.3.17 Vulnerable ·streetwriters

Remediation

  • Fix · CNA Notesnook Web/Desktop (streetwriters) Fixed in 3.3.11
  • Fix · CNA Notesnook iOS/Android (streetwriters) Fixed in 3.3.17

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33976

References

Exploit 1

  • TI-2026-26305 Notesnook vulnerable to RCE via stored XSS in Note History diff viewer CVSS 3.1HIGH 8.6
  • TI-2026-30458 Notesnook: RCE via stored XSS in note export rendering CVSS 3.1CRITICAL 9.6
  • TI-2026-24428 Notesnook has Stored XSS via unsanitized Twitter/X embed URL in editor (`tweetToEmbed`) CVSS 3.1MEDIUM 5.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences