Htmlsanitizer CVEs and Security Vulnerabilities

CVE-2026-116538

HtmlSanitizer before 9.2.1039 XSS via SanitizeDom Body and HTML Attributes

HtmlSanitizer before 9.2.1039 and 10.0 prereleases before 10.0.1037-beta contains a cross-site scripting vulnerability because SanitizeDom(string) never sanitizes attributes on the html and body wrapper elements. Attackers can supply input with a second body or html tag carrying event handlers like onload, executing script when applications render serialized document or body outer HTML.

CVSS 4.0 · 2.3 Low EPSS < 1% KEV · Not listed

Vendors

Htmlsanitizer Project Mganss

Products

Htmlsanitizer Htmlsanitizer

CVE-2026-25543

HtmlSanitizer has a bypass via template tag

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 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed