CVE intelligence and bounded remediation

CVE-2025-66021 — Owasp Java Html Sanitizer security vulnerability

High CVSS 8.6

OWASP Java HTML Sanitizer is a configureable HTML Sanitizer written in Java, allowing inclusion of HTML authored by third-parties in web applications while protecting against XSS. In version 20240325.1, OWASP java html sanitizer is vulnerable to XSS if HtmlPolicyBuilder allows noscript and style tags with allowTextIn inside the style tag. This could lead to XSS if the payload is crafted in such a way that it does not sanitise the CSS and allows tags which is not mentioned in HTML policy. At time of publication no known patch is available.

Severity
High
CVSS
8.6 (4.0)
Published
2025-11-26
CISA KEV
Not currently listed
Ecosystem
java/maven
Weaknesses
CWE-79

Affected products

  • owasp / java_html_sanitizer / 20240325.1

Matched remediation archetype

Cross-site scripting and unsafe browser output

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Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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