CVE-2025-66400
mdast-util-to-hast is an mdast utility to transform to hast. From 13.0.0 to before 13.2.1, multiple (unprefixed) classnames could be added in markdown source by using character references. This could make rendered user supplied markdown code elements appear like the rest of the page. This vulnerability is fixed in 13.2.1.
Published:Dec 1, 2025
Last Modified:Feb 6, 2026
EPS:Dec 1, 2025
EPSS Score:0.00073
CVSS Score:5.3
Affected Products
Vendor
Product
Action
Vendor
Syntax-tree
Product
Mdast-util-to-hast
Syntax-tree
Mdast-util-to-hast
Vendor
Unifiedjs
Product
Mdast-util-to-hast
Unifiedjs
Mdast-util-to-hast
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
