CVE-2026-31876CWE-79

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

Medium · published March 11, 2026

CVSS v3.1
5.4
EPSS
0%
Percentile
15.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00249 · 15.3th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-03-11T18:17Z
EPSS history
Timeline
  • 11 MAR 18:17Z
    Notesnook has Stored XSS via unsanitized Twitter/X embed URL in editor (`tweetToEmbed`)
    cvelistv5