CVE-2021-39199

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.

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.

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

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.

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.

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