CVE-2026-42090: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in streetwriters notesnook
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.
AI Analysis
Technical Summary
Notesnook versions before 3.3.15 (Web/Desktop) and 3.3.20 (iOS/Android) suffer from a stored XSS vulnerability in the note export flow. Exported note fields such as title, headline, and content are embedded into an HTML template without HTML escaping. When exporting to PDF, Notesnook renders this HTML inside a same-origin, unsandboxed iframe using iframe.srcdoc, enabling injected scripts to execute within the Notesnook origin. On the desktop app, Electron's configuration (nodeIntegration: true and contextIsolation: false) allows this script execution to escalate to remote code execution. The issue is fixed in the stated patched versions.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary scripts in the context of the Notesnook origin during note export. On the desktop app, this leads to remote code execution due to Electron's insecure settings, potentially compromising user data and system integrity. The CVSS score of 9.6 reflects the critical severity with network attack vector, low attack complexity, no privileges required, user interaction needed, and high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix is available and has been released in Notesnook Web/Desktop version 3.3.15 and Notesnook iOS/Android version 3.3.20. Users and administrators should upgrade to these or later versions to remediate the vulnerability. No additional mitigations are specified or required beyond applying the official patches.
CVE-2026-42090: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in streetwriters notesnook
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Notesnook versions before 3.3.15 (Web/Desktop) and 3.3.20 (iOS/Android) suffer from a stored XSS vulnerability in the note export flow. Exported note fields such as title, headline, and content are embedded into an HTML template without HTML escaping. When exporting to PDF, Notesnook renders this HTML inside a same-origin, unsandboxed iframe using iframe.srcdoc, enabling injected scripts to execute within the Notesnook origin. On the desktop app, Electron's configuration (nodeIntegration: true and contextIsolation: false) allows this script execution to escalate to remote code execution. The issue is fixed in the stated patched versions.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary scripts in the context of the Notesnook origin during note export. On the desktop app, this leads to remote code execution due to Electron's insecure settings, potentially compromising user data and system integrity. The CVSS score of 9.6 reflects the critical severity with network attack vector, low attack complexity, no privileges required, user interaction needed, and high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix is available and has been released in Notesnook Web/Desktop version 3.3.15 and Notesnook iOS/Android version 3.3.20. Users and administrators should upgrade to these or later versions to remediate the vulnerability. No additional mitigations are specified or required beyond applying the official patches.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-23T19:17:30.566Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f8d219cbff5d86103970ae
Added to database: 5/4/2026, 5:06:33 PM
Last enriched: 5/4/2026, 5:21:32 PM
Last updated: 5/4/2026, 6:14:33 PM
Views: 4
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