Medium 5.4Published Mar 11, 2026

CVE-2026-31876Notesnook has Stored XSS via unsanitized Twitter/X embed URL in editor (`tweetToEmbed`)

Updated under an hour ago (Oct 27, 2026, 5:50 PM ET)

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It affects streetwriters notesnook and 2 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for streetwriters notesnook

Exploited in the last 30 days

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: 5.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Mar 12, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

streetwriters notesnook streetwriters:notesnook (from the name)	before 3.3.9	CNA record
streetwriters notesnook_desktop streetwriters:notesnook_desktop	before 3.3.9	NVD
streetwriters notesnook_mobile streetwriters:notesnook_mobile	before 3.3.15; before 3.3.15	NVD

References

References

https://github.com/streetwriters/notesnook/security/advisories/GHSA-jprx-2w2h-4rh5	x-refsource-confirm, vendor-advisory
https://github.com/streetwriters/notesnook/commit/e87f5e5f899f45df28d7c0f33f15e9178d1fbcb7	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.