CVE-2026-31876 — Notesnook has Stored XSS via unsanitized Twitter/X embed URL in editor (`tweetToEmbed`)
Notesnook is a note-taking app focused on user privacy & ease of use. Prior to 3.3.9, a Stored Cross-Site Scripting (XSS) vulnerability existed in Notesnook's editor embed compo…
Published: 2026-03-11 · CVSS: 5.4 · CVSS 3.1
Notesnook is a note-taking app focused on user privacy & ease of use. Prior to 3.3.9, a Stored Cross-Site Scripting (XSS) vulnerability existed in Notesnook's editor embed component when rendering Twitter/X embed URLs. The tweetToEmbed() function in component.tsx interpolated the user-supplied URL directly into an HTML string without escaping, which was then assigned to the srcdoc attribute of an <iframe>. This vulnerability is fixed in 3.3.9.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7