PT-2026-24783 · Git+1 · Notesnook+2

X4Sh3S · CVE-2026-31876 · Published 2026-03-11 · Updated 2026-03-12

Positive Technologies (AI Summary)

CVSS v3.1

5.4

Medium

Base vector

AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Name of the Vulnerable Software and Affected Versions Notesnook versions prior to 3.3.9

Description A Stored Cross-Site Scripting (XSS) issue existed in Notesnook’s editor embed component when processing Twitter/X embed URLs. The tweetToEmbed() function within component.tsx directly incorporated user-provided URLs into an HTML string without proper escaping before assigning it to the srcdoc attribute of an <iframe>. This allowed for the injection of malicious scripts.

Recommendations Update Notesnook to version 3.3.9 or later.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-31876

GHSA-JPRX-2W2H-4RH5

Affected Products

Notesnook

Notesnook Desktop

Notesnook Mobile

References · 6

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31876.json · Exploit
• https://github.com/streetwriters/notesnook/commit/e87f5e5f899f45df28d7c0f33f15e9178d1fbcb7 · Patch
• https://github.com/streetwriters/notesnook/security/advisories/GHSA-jprx-2w2h-4rh5 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-31876 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-31876 · Security Note
• https://twitter.com/CVEnew/status/2031992389032972736 · Twitter Post