Vulnerability · Published Sep 7, 2021 · Assigned by GitHub_M
CVE-2021-39199Cross site scripting via unsafe defaults in remark-html
Critical 10.0
In plain English
A critical-severity cross-site scripting in remark-html from remarkjs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | remark-html | 13.0.2 | GHSA-9q5w-79cv-947m |
| npm | remark-html | 14.0.1 | GHSA-9q5w-79cv-947m |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| remarkjs | remark-html | >= 14.0.0, < 14.0.1< 13.0.2 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
References
- https://github.com/remarkjs/remark-html/security/advisories/GHSA-9q5w-79cv-947m x_refsource_CONFIRM
- https://github.com/remarkjs/remark-html/commit/b75c9dde582ad87ba498e369c033dc8a350478c1 x_refsource_MISC
- https://github.com/remarkjs/remark-html/releases/tag/14.0.1 x_refsource_MISC
- https://www.npmjs.com/package/remark-html x_refsource_MISC