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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 5
https://github.com/Milkdown/milkdown/commit/db1ae721854a0ab2f188b83cf8695702966…
disclosure@vulncheck.com
https://github.com/Milkdown/milkdown/pull/2410
disclosure@vulncheck.com
https://github.com/Milkdown/milkdown/releases/tag/v7.21.3
disclosure@vulncheck.com
https://www.npmjs.com/package/@milkdown/plugin-emoji
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/milkdown-dom-xss-via-innerhtml-assignment
disclosure@vulncheck.com