Medium 5.3Published Dec 1, 2025

CVE-2025-66400mdast-util-to-hast is an mdast utility to transform to hast.

Updated under an hour ago (2026-10-19 10:00 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for unifiedjs mdast-util-to-hast

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE): CWE-20, CWE-915
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Oct 18, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

unifiedjs mdast-util-to-hast unifiedjs:mdast-util-to-hast	from 13.0.0 before 13.2.1	NVD

References

https://github.com/syntax-tree/mdast-util-to-hast/commit/6fc783ae6abdeb798fd5a68e7f3f21411dde7403patch
https://github.com/syntax-tree/mdast-util-to-hast/commit/ab3a79570a1afbfa7efef5d4a0cd9b5caafbc5d7patch
https://github.com/syntax-tree/mdast-util-to-hast/security/advisories/GHSA-4fh9-h7wg-q85mvendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.