Ammonia

ammonia is a Rust library for repairing and securing untrusted HTML. Prior to 3.3.3, 4.0.3, and 4.1.4, applications that allow the SVG animate or set elements can retain an animation whose attributeName targets href and whose value uses the javascript scheme. The sanitized SVG can therefore create a script-bearing link, and a user who clicks the link can execute attacker-controlled script in the application's origin, enabling stored cross-site scripting. This issue is fixed in versions 3.3.3, 4.0.3, and 4.1.4.

Published: 2026-10-13T14:28:50.011Z
Updated: 2026-10-13T20:23:10.660Z

ammonia is a Rust library for repairing and securing untrusted HTML. Prior to 3.3.2, 4.0.2, and 4.1.3, applications that explicitly allow the math tag, annotation-xml, and at least one raw-text HTML element while disallowing the encoding attribute can permit mutation cross-site scripting. ammonia does not correctly implement annotation-xml's encoding-dependent MathML integration-point behavior after attribute filtering removes encoding, so the sanitizer validates a descendant under one namespace interpretation while the browser reparses the output under another. An attacker can use that namespace transition and an allowed raw-text HTML element to execute JavaScript when a user renders the sanitized output. The required tags are not enabled by default, so applications that do not explicitly allow them are not affected. This issue is fixed in versions 3.3.2, 4.0.2, and 4.1.3.

Published: 2026-10-15T18:10:35.869Z
Updated: 2026-10-15T20:25:49.464Z