GHSA-f5ww-cq3m-q3g7

### Impact

Using carefully crafted input, an attacker may be able to sneak arbitrary HTML and CSS through Sanitize `>= 3.0.0, < 6.0.2` when Sanitize is configured to use the built-in "relaxed" config or when using a custom config that allows `style` elements and one or more CSS at-rules. This could result in XSS (cross-site scripting) or other undesired behavior when the malicious HTML and CSS are rendered in a browser.

### Patches

Sanitize `>= 6.0.2` performs additional escaping of CSS in `style` element content, which fixes this issue.

### Workarounds

Users who are unable to upgrade can prevent this issue by using a Sanitize config that doesn't allow `style` elements, using a Sanitize config that doesn't allow CSS at-rules, or by manually escaping the character sequence `</` as `<\/` in `style` element content.

### Credit

This issue was found by @cure53 during an audit of a project that uses Sanitize and was reported by one of that project's maintainers. Thank you!