mdast-util-to-hast has unsanitized class attribute

TRUNG BÌNH 5.3CVE-2025-66400 · GHSA-4fh9-h7wg-q85m · Công bố 01/12/2025 · cập nhật 18/10/2026

Tóm tắt nhanh

CVE-2025-66400 là lỗ hổng mức TRUNG BÌNH (CVSS 5.3) ảnh hưởng mdast-util-to-hast (unifiedjs), mdast-util-to-hast.
Xác suất bị khai thác trong 30 ngày tới (EPSS): 0.33%, cao hơn 25.9% các lỗ hổng khác.
Cách xử lý: cập nhật lên 13.2.1 hoặc mới hơn.

Gói / sản phẩm	Phiên bản bị ảnh hưởng	Phiên bản đã vá
mdast-util-to-hast unifiedjs	`≥ 13.0.0, < 13.2.1`	`13.2.1`
mdast-util-to-hast npm	`≥ 13.0.0, < 13.2.1`	`13.2.1`

Mô tả

Impact

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. The following markdown:

```js&#x20;xss
```

Would create <pre><code class="language-js xss"></code></pre> If your page then applied .xss classes (or listeners in JS), those apply to this element. For more info see https://github.com/ChALkeR/notes/blob/master/Improper-markup-sanitization.md#unsanitized-class-attribute

Patches

The bug was patched. When using regular semver, run npm install. For exact ranges, make sure to use 13.2.1.

Workarounds

Update.

References

Mô tả của NVD

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.