What is the CVSS score of CVE-2026-31876?

CVE-2026-31876 has a CVSS 3.1 base score of 5.4 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Notesnook Mobile are affected by CVE-2026-31876?

Organizations using Notesnook should be aware of moderate risk from CVE-2026-31876, a cross-site scripting vulnerability rated CVSS 5.4.

How to fix or mitigate CVE-2026-31876?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Notesnook Mobile CVE-2026-31876

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-03-11 security-advisories@github.com

XSS Notesnook Mobile Notesnook Desktop

5.4

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

5.4 MEDIUM

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:07 vuln.today

CVE Published

Mar 11, 2026 - 19:16 nvd

MEDIUM 5.4

DescriptionGitHub Advisory

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.

AnalysisAI

Stored XSS in Notesnook Mobile and Desktop versions prior to 3.3.9 allows authenticated users to execute arbitrary JavaScript by injecting malicious code into Twitter/X embed URLs through the editor component. An attacker with user account access can craft a malicious note containing a specially crafted embed URL that executes when the note is viewed, potentially compromising user data or session tokens. No patch is currently available for affected versions.

Technical ContextAI

Classified as CWE-79 (Cross-site Scripting (XSS)). Affects ease of use.. 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.

RemediationAI

Fixed in version 3.3.9.. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.