CVE-2021-47837 affects Markdownify 1.2.0, a markdown file editor application. The vulnerability is a persistent cross-site scripting (XSS) flaw that allows attackers to embed malicious scripts within markdown files. When these crafted files are opened by users, the embedded scripts execute automatically. This can potentially lead to remote code execution on the victim's system. The vulnerability has been assigned a high criticality rating and exploit code is publicly available.