HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. In HtmlSanitizer before version 5.0.372, there is a possible XSS bypass if style tag is allowed. If you have explicitly allowed the `<style>` tag, an attacker could craft HTML that includes script after passing through the sanitizer. The default settings disallow the `<style>` tag so there is no risk if you have not explicitly allowed the `<style>` tag. The problem has been fixed in version 5.0.372.

Affected: NuGet: HtmlSanitizer

### Impact

If you have explicitly allowed the `<style>` tag, an attacker could craft HTML that includes script after passing through the sanitizer. The default settings disallow the `<style>` tag so there is no risk if you have not explicitly allowed the `<style>` tag.

### Patches

The problem has been fixed in version 5.0.372.

### Workarounds

Remove the `<style>` tag from the set of allowed tags.

### For more information

If you have any questions or comments about this advisory open an issue in https://github.com/mganss/HtmlSanitizer

### Credits

This issue was discovered by Michal Bentkowski of Securitum.