Vulnerability Description
HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special tag that does not usually render its contents, unless the shadowrootmode attribute is set to open or closed. This issue has been patched in versions 9.0.892 and 9.1.893-beta.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Htmlsanitizer Project | Htmlsanitizer | < 9.0.892 |
Related Weaknesses (CWE)
References
- https://github.com/mganss/HtmlSanitizer/commit/0ac53dca30ddad963f2b243669a506693Patch
- https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-j92c-7v7g-gj3fMitigationPatchVendor Advisory
- https://www.nuget.org/packages/HtmlSanitizer/9.0.892ProductRelease Notes
- https://www.nuget.org/packages/HtmlSanitizer/9.1.893-betaProductRelease Notes
FAQ
What is CVE-2026-25543?
CVE-2026-25543 is a vulnerability with a CVSS score of 6.1 (MEDIUM). HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its ...
How severe is CVE-2026-25543?
CVE-2026-25543 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-25543?
Check the references section above for vendor advisories and patch information. Affected products include: Htmlsanitizer Project Htmlsanitizer.