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OpenAdvisories
Medium · 5.4 CVE-2026-31876 EUVD-2026-11286

Notesnook has Stored XSS via unsanitized Twitter/X embed URL in editor (`tweetToEmbed`)

Published Mar 11, 2026 · Updated Mar 12, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
streetwriters notesnook < 3.3.9 —

References