CVE-2026-57530

8th percentile - higher than 8% of all known CVEs

Milkdown before 7.21.3 contains a stored cross-site scripting vulnerability in the @milkdown/preset-commonmark and @milkdown/components packages that allows attackers with document write access to execute arbitrary JavaScript in the browser context of any user who opens the document or clicks a rendered link. The parseMarkdown runner stores raw URL values from the remark AST as href mark attributes without URL scheme validation, and the ineffective DOMPurify.sanitize call in edit-view.ts treats the bare URL string as a text node and returns it unchanged, allowing javascript: payloads to pass through the link-tooltip preview component and read-only mode anchor elements unmodified.

An attacker can inject malicious JavaScript into a document that will be executed in other users' browsers, potentially leading to data theft, session hijacking, or further attacks.

Update Milkdown to version 7.21.3 or later, which fixes this vulnerability, and implement URL scheme validation for all links in documents.