Description

XSS in ammonia via SVG animate and set animation tags The following SVG will produce a link with a javascript scheme. If the user clicks this link, they will run it.

<svg xmlns="http://www.w3.org/2000/svg">
  <a>
    <set attributeName="href" to="javascript:alert('SET_XSS')"></set>
    <text y="30">Click set</text>
  </a>
</svg>

Ammonia did not apply attribute filters based on attributeName, so the contents of the to, from, and values tags were not sanitized as URLs.

Applications that do not explicitly allow either of these tags should not be affected, since neither are allowed by default.

Discovered by: Younghun Ko (@koyokr)

Mitigation

Aliases