In libarchive before 3.6.2 the software does not check for an error after calling calloc function that can return with a NULL pointer if the function fails which leads to a resultant NULL pointer dereference. NOTE: the discoverer cites this CWE-476 remark but third parties dispute the code-execution impact: "In rare circumstances when NULL is equivalent to the 0x0 memory address and privileged code can access it then writing or reading memory is possible which may lead to code execution."