CVE-2025-66400
Medium
Description
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.
SeverityMedium
CVSS5.3
Exploit probability—
ProductUnifiedjs Mdast-util-to-hast
PublishedDec 1, 2025
First seenDec 1, 2025
Weakness typeCWE-20Improper input validationCWE-915CWE-915
How to fix
Update
- unifiedjs mdast-util-to-hast13.2.1 or later
- mdast-util-to-hast13.2.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| unifiedjs mdast-util-to-hast | 13.0.0 ≤ v < 13.2.1 | 13.2.1 |
| mdast-util-to-hastnpm | 13.0.0 ≤ v < 13.2.1 | 13.2.1 |
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