CVE-2024-21535: markdown-to-jsx XSS — Fix

Description

Versions of the package markdown-to-jsx before 7.4.0 are vulnerable to Cross-site Scripting (XSS) via the src property due to improper input sanitization. An attacker can execute arbitrary code by injecting a malicious iframe element in the markdown.

Is your site exposed to CVE-2024-21535?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

6.1

MEDIUM

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
quantizor	markdown-to-jsx	< 7.4.0

References

Advisories & Patches

https://github.com/quantizor/markdown-to-jsx/commit/8eb74da825c0d8d2e9508d73c672bcae36ba555a

Other References

https://security.snyk.io/vuln/SNYK-JS-MARKDOWNTOJSX-6258886

Frequently Asked Questions

What is CVE-2024-21535? +

Versions of the package markdown-to-jsx before 7.4.0 are vulnerable to Cross-site Scripting (XSS) via the src property due to improper input sanitization. An attacker can execute arbitrary code by injecting a malicious iframe element in the markdown. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2024-21535? +

CVE-2024-21535 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-21535? +

CVE-2024-21535 affects products from quantizor, specifically: markdown-to-jsx. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-21535? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-40282

WeGIA is a web manager for charitable institutions. In versions prior to 3.6.10, a Stored Cross-Site Scripting (XSS) vulnerability allows …

CVE-2026-3317

Reflected Cross-Site Scripting (XSS) vulnerability in Navigate Content Management System. The vulnerability is present in the '/blog' endpoint because user …

CVE-2025-10354

Cross-Site Scripting (XSS) vulnerability reflected in Semantic MediaWiki. This vulnerability allows an attacker to execute JavaScript code in the victim's …

CVE-2026-41456

Bludit CMS prior to commit 6732dde contains a reflected cross-site scripting vulnerability in the search plugin that allows unauthenticated attackers …

CVE-2026-40872

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover …

CVE-2026-40878

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the mailcow web interface …

CVE-2024-21535