CVE-2026-57531

16th percentile - higher than 16% of all known CVEs

Milkdown before 7.21.3 contains a DOM cross-site scripting vulnerability in the @milkdown/plugin-emoji package that allows unauthenticated attackers to execute arbitrary JavaScript in the host application's origin by causing a victim to paste attacker-controlled content. The parseDOM.getAttrs handler stores raw innerHTML of pasted span elements with data-type="emoji" without sanitization, and the toMarkdown runner subsequently assigns this unsanitized value directly to a live DOM element's innerHTML, bypassing the DOMPurify sanitization used in the toDOM path, causing payload execution on every markdown serialization cycle.

An attacker can execute arbitrary JavaScript in the victim's browser, potentially leading to session theft, content modification, or further attacks on application users.

Update Milkdown to version 7.21.3 or later, which fixes this vulnerability, and consider additional input sanitization in the paste functionality.