VulnerabilityAnalyzed

CVE-2026-31876

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.

MEDIUM 5.4EPSS 0.17%

Does this matter?

Lower severity and a low EPSS score (0.17%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1: 5.4 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS: 0.17% probability · 7th percentile
CISA KEV: Not listed
Weakness: CWE-79
Affected: streetwriters/notesnook desktop · streetwriters/notesnook mobile
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.