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Unsafe defaults in `remark-html`

Critical
wooorm published GHSA-9q5w-79cv-947m Sep 7, 2021

Package

npm remark-html (npm)

Affected versions

<13.0.2, 14.0.0

Patched versions

13.0.2, 14.0.1

Description

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:

Severity

Critical

CVE ID

CVE-2021-39199

Weaknesses

No CWEs

Credits