Cross-Site Scripting (XSS) vulnerability found in MarkTwo commit e3a1d3f90cce4ea9c26efcbbf3a1cbfb9dcdb298 (May 2025) allows a remote attacker to execute arbitrary code via a crafted script input to the editor interface. The application does not properly sanitize user-supplied Markdown before rendering it. Successful exploitation could lead to session hijacking, credential theft, or arbitrary client-side code execution in the context of the victim's browser.
https://marktwo.app/try-it-now
https://github.com/anthonygarvan/marktwo
https://github.com/0x72303074/CVE-Disclosures/tree/main/MarkTwo%20Markdown%20Editor/CVE-2025-51691