A maliciously crafted DWF file, when parsed in w3dtk.dll through Autodesk Navisworks, can force a Use-After-Free. A malicious actor can leverage this vulnerability to cause a crash or execute arbitrary code in the context of the current process.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.