CVE-2026-5751

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

CVE-2026-5751

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

CVE-2026-5751

justhtml versions 1.13.0 and earlier are affected by a parser-differential / mutation XSS (mXSS) vulnerability. The issue occurs when a custom SanitizationPolicy preserves foreign namespaces (e.g., drop_foreign_namespaces=False with allowlisted SVG/MathML elements or raw-text containers such as )...

CVE-2026-5751 justhtml before 1.14.0 Mutation XSS via custom sanitization policies

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

CVE-2026-5751 justhtml before 1.14.0 Mutation XSS via custom sanitization policies

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

EUVD-2026-64654

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

PT-2026-79771

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., drop foreign namespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

CVE-2026-5751: Improper Neutralization of Input During Web Page Generation

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

PT-2026-33573

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...