Confidentiality
Read Memory
If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
Availability
DoS: Crash, Exit, or Restart
If the untrusted pointer references a memory location that is not accessible to the program, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly.
Integrity, Confidentiality, Availability
Execute Unauthorized Code or Commands, Modify Memory
If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.