Unsafe defaults in `remark-html`
Impact
The documentation of remark-html has mentioned that it was safe by default. In practise the default was never safe and had to be opted into. This means arbitrary HTML can be passed through leading to potential XSS attacks.
Patches
The problem has been patched in 13.0.2 and 14.0.1: remark-html is now safe by default, and the implementation matches the documentation.
Workarounds
On older affected versions, pass sanitize: true, like so:
- .use(remarkHtml)
+ .use(remarkHtml, {sanitize: true})References
n/a
For more information
If you have any questions or comments about this advisory:
- Open an issue in
remark-html - Email us at security@unifiedjs.com
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | remark-html | < 13.0.2, >= 14.0.0, < 14.0.1 | 13.0.2, 14.0.1 |
References
- https://github.com/remarkjs/remark-html/security/advisories/GHSA-9q5w-79cv-947m
- https://nvd.nist.gov/vuln/detail/CVE-2021-39199
- https://github.com/remarkjs/remark-html/commit/b75c9dde582ad87ba498e369c033dc8a350478c1
- https://github.com/remarkjs/remark-html
- https://github.com/remarkjs/remark-html/releases/tag/14.0.1
- https://www.npmjs.com/package/remark-html
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N- Weakness (CWE)
CWE-79- Platform
- npm
- Package
remark-html- Disclosed
- 07.09.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-9q5w-79cv-947m - CC BY 4.0
Vulnerability history: remark-html
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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