streetwriters notesnook cross site scripting

Summaryinfo

A vulnerability was found in streetwriters notesnook. It has been declared as problematic. Affected is an unknown function. Such manipulation leads to cross site scripting. This vulnerability is uniquely identified as CVE-2026-42090. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in streetwriters notesnook (version now known). It has been rated as problematic. Affected by this issue is some unknown processing. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-42090 since 04/23/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading eliminates this vulnerability. The upgrade is hosted for download at github.com.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• streetwriters

Name

• notesnook

Website

• Product: https://github.com/streetwriters/notesnook/

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Once again VulDB remains the best source for vulnerability data.

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