CVE-2026-31876 Notesnook has Stored XSS via unsanitized Twitter/X embed URL in editor (`tweetToEmbed`)
Attackers can inject malicious scripts via Twitter embed URLs in Notesnook, potentially stealing user data or taking over accounts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-31876?
CVE-2026-31876 is a medium-severity cross-site scripting vulnerability in streetwriters notesnook, published on 11 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-31876?
It affects 2 products.
Products include Streetwriters Notesnook Desktop, Streetwriters Notesnook Mobile.
How do I fix CVE-2026-31876?
No fix has been published for CVE-2026-31876 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-31876 being exploited?
There is no known exploitation of CVE-2026-31876 in the wild and no public exploit code.
Other vulnerabilities in streetwriters notesnook
Sources
Also known as GHSA-jprx-2w2h-4rh5.