WebKit/Source/core/layout/LayoutBlock.cpp in Blink, as used in Google Chrome before 49.0.2623.75, does not properly determine when anonymous block wrappers may exist, which allows remote attackers to cause a denial of service (incorrect cast and assertion failure) or possibly have unspecified other impact via crafted JavaScript code.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.