XSS in HtmlSanitizer

TRUNG BÌNH 6.1CVE-2020-26293 · GHSA-8j9v-h2vp-2hhv · Công bố 04/01/2021 · cập nhật 17/06/2026

Tóm tắt nhanh

CVE-2020-26293 là lỗ hổng mức TRUNG BÌNH (CVSS 6.1) ảnh hưởng HtmlSanitizer, htmlsanitizer (htmlsanitizer project).
Xác suất bị khai thác trong 30 ngày tới (EPSS): 1.0%, cao hơn 63.3% các lỗ hổng khác.
Cách xử lý: cập nhật lên 5.0.372 hoặc mới hơn.

Gói / sản phẩm	Phiên bản bị ảnh hưởng	Phiên bản đã vá
HtmlSanitizer NuGet	`< 5.0.372`	`5.0.372`
htmlsanitizer htmlsanitizer_project	`< 5.0.372`	`5.0.372`

Mô tả

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.

Mô tả của NVD

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.