CVE-2025-66400

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. 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.

5.3 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References
Link Resource
https://github.com/syntax-tree/mdast-util-to-hast/commit/6fc783ae6abdeb798fd5a68e7f3f21411dde7403 Patch
https://github.com/syntax-tree/mdast-util-to-hast/commit/ab3a79570a1afbfa7efef5d4a0cd9b5caafbc5d7 Patch
https://github.com/syntax-tree/mdast-util-to-hast/security/advisories/GHSA-4fh9-h7wg-q85m Vendor Advisory
Configurations

Configuration 1 (hide)

cpe:2.3:a:unifiedjs:mdast-util-to-hast:*:*:*:*:*:node.js:*:*
History

06 Feb 2026, 16:36

Type Values Removed Values Added
CPE cpe:2.3:a:syntax-tree:mdast-util-to-hast:*:*:*:*:*:*:*:* cpe:2.3:a:unifiedjs:mdast-util-to-hast:*:*:*:*:*:node.js:*:*
First Time Unifiedjs mdast-util-to-hast
Unifiedjs

06 Feb 2026, 16:17

Type Values Removed Values Added
CPE cpe:2.3:a:syntax-tree:mdast-util-to-hast:*:*:*:*:*:*:*:*
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.3
CWE NVD-CWE-Other
First Time Syntax-tree mdast-util-to-hast
Syntax-tree
References () https://github.com/syntax-tree/mdast-util-to-hast/commit/6fc783ae6abdeb798fd5a68e7f3f21411dde7403 - () https://github.com/syntax-tree/mdast-util-to-hast/commit/6fc783ae6abdeb798fd5a68e7f3f21411dde7403 - Patch
References () https://github.com/syntax-tree/mdast-util-to-hast/commit/ab3a79570a1afbfa7efef5d4a0cd9b5caafbc5d7 - () https://github.com/syntax-tree/mdast-util-to-hast/commit/ab3a79570a1afbfa7efef5d4a0cd9b5caafbc5d7 - Patch
References () https://github.com/syntax-tree/mdast-util-to-hast/security/advisories/GHSA-4fh9-h7wg-q85m - () https://github.com/syntax-tree/mdast-util-to-hast/security/advisories/GHSA-4fh9-h7wg-q85m - Vendor Advisory

01 Dec 2025, 23:15

Type Values Removed Values Added
New CVE
Information

Published : 2025-12-01 23:15

Updated : 2026-02-06 16:36

NVD link : CVE-2025-66400

Mitre link : CVE-2025-66400

CVE.ORG link : CVE-2025-66400

JSON object : View

Products Affected

unifiedjs

  • mdast-util-to-hast
CWE
CWE-20

Improper Input Validation

CWE-915

Improperly Controlled Modification of Dynamically-Determined Object Attributes

NVD-CWE-Other