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TI-2026-30458 Aliases CVE-2026-42090

Notesnook: RCE via stored XSS in note export rendering

Priority MEDIUM 43CWE-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
No fix listed

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 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00477 41st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
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
streetwritersnotesnookNotesnook Web/Desktop < 3.3.15; Notesnook iOS/Android < 3.3.20—No fix listedCNA
  • notesnook Vendorstreetwriters Affected Notesnook Web/Desktop < 3.3.15; Notesnook iOS/Android < 3.3.20 Fixed in — No fix listed CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:streetwriters:notesnook_desktop:*:*:*:*:*:*:*:*before 3.3.15Vulnerablestreetwriters
cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:android:*:*before 3.3.20Vulnerablestreetwriters
cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:iphone_os:*:*before 3.3.20Vulnerablestreetwriters
  • cpe:2.3:a:streetwriters:notesnook_desktop:*:*:*:*:*:*:*:* Versions before 3.3.15 Vulnerable ·streetwriters
  • cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:android:*:* Versions before 3.3.20 Vulnerable ·streetwriters
  • cpe:2.3:a:streetwriters:notesnook_mobile:*:*:*:*:*:iphone_os:*:* Versions before 3.3.20 Vulnerable ·streetwriters

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42090
  2. 2026-10-25 EPSS moved to the below the 50th percentile

References

Advisory 1

Other 2

  • TI-2026-26317 Notesnook vulnerable to RCE via stored XSS in Web Clipper rendering CVSS 3.1CRITICAL 9.7
  • TI-2026-26305 Notesnook vulnerable to RCE via stored XSS in Note History diff viewer CVSS 3.1HIGH 8.6
  • 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