CVE-2021-39199

Name: CVE-2021-39199
Creator: NVD / NIST
Published: 2021-09-07T19:15:08.747+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 1.04%

Last modified Jun 17, 2026

CVE-2021-39199 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. remark-html is an open source nodejs library which compiles Markdown to HTML. In affected versions the documentation of remark-html has mentioned that it was safe by default. EPSS estimates a 1.04% chance of exploitation in the next 30 days.

Description

remark-html is an open source nodejs library which compiles Markdown to HTML. In affected versions the documentation of remark-html has mentioned that it was safe by default. In practice the default was never safe and had to be opted into. That is, user input was not sanitized. This means arbitrary HTML can be passed through leading to potential XSS attacks. 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. On older affected versions, pass `sanitize: true` if you cannot update.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

1.04%

59.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Remark	Remark-Html	< 13.0.2
Remark	Remark-Html	>= 14.0.0, < 14.0.1

References

https://github.com/remarkjs/remark-html/commit/b75c9dde582ad87ba498e369c033dc8a350478c1Patch, Third Party Advisory
https://github.com/remarkjs/remark-html/releases/tag/14.0.1Patch, Release Notes, Third Party Advisory
https://github.com/remarkjs/remark-html/security/advisories/GHSA-9q5w-79cv-947mPatch, Third Party Advisory
https://www.npmjs.com/package/remark-htmlProduct, Third Party Advisory
https://github.com/remarkjs/remark-html/commit/b75c9dde582ad87ba498e369c033dc8a350478c1Patch, Third Party Advisory
https://github.com/remarkjs/remark-html/releases/tag/14.0.1Patch, Release Notes, Third Party Advisory
https://github.com/remarkjs/remark-html/security/advisories/GHSA-9q5w-79cv-947mPatch, Third Party Advisory
https://www.npmjs.com/package/remark-htmlProduct, Third Party Advisory

Timeline

Published: Sep 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-39199?

How severe is CVE-2021-39199?

CVE-2021-39199 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 1.04% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39199?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-39199?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST