Versions of markdown-to-jsx prior to 6.11.4 are vulnerable to Cross-Site Scripting. Due to insufficient input sanitization the package may render output containing malicious JavaScript. This vulnerability can be exploited through input of links containing data or VBScript URIs and a base64-encoded payload.

Recommendation

Upgrade to version 6.11.4 or later.

References

• quantizor/markdown-to-jsx#307
• https://www.npmjs.com/advisories/1219