CVE-2021-47838 affects Markright 1.0, a markdown editor application. The vulnerability is a persistent cross-site scripting (XSS) flaw that allows attackers to embed malicious JavaScript payloads within markdown files. When victims open these specially crafted markdown files, the malicious code executes automatically. This XSS vulnerability can potentially lead to remote code execution on the victim's system. The vulnerability has been documented with proof-of-concept exploits available publicly. Markright is available on GitHub and this vulnerability represents a significant security risk for users of the application.