justhtml has sanitization bypass in custom policies and programmatic DOM

Summary justhtml 1.17.0 fixes multiple security issues in sanitization, serialization, and programmatic DOM handling. Most of these issues affected advanced or custom configurations rather than the default safe path. Affected versions - justhtml , MathML , SVG / , and MathML text integration poin...

Multiple security fixes in justhtml

Summary justhtml 1.16.0 fixes multiple security issues in sanitization, serialization, and programmatic DOM handling. Most of these issues affected one of these advanced paths rather than ordinary parsed HTML with the default safe settings: - programmatic DOM input to sanitize or sanitizedom -...

Cross-site Scripting (XSS)

Overview justhtml is an A pure Python HTML5 parser that just works. Affected versions of this package are vulnerable to Cross-site Scripting XSS via the custom SanitizationPolicy if configured with dropforeignnamespaces=False or allowlisted foreign elements such as MathML or SVG or raw-text...

GHSA-R758-8HXW-4845 justhtml: Mutation XSS with custom foreign-namespace sanitization policies

Summary A parser-differential / mutation XSS issue was found in justhtml when using a custom sanitization policy that preserves foreign namespaces such as SVG or MathML. Under these custom settings, specially crafted input could sanitize into HTML that looked safe at first, but became unsafe when...

justhtml: Mutation XSS with custom foreign-namespace sanitization policies

Summary A parser-differential / mutation XSS issue was found in justhtml when using a custom sanitization policy that preserves foreign namespaces such as SVG or MathML. Under these custom settings, specially crafted input could sanitize into HTML that looked safe at first, but became unsafe when...