CWE-590
Free of Memory not on the Heap
AI Translation Available
The product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().
Status
incomplete
Abstraction
variant
Affected Platforms
C
Memory-Unsafe
Extended Description
AI Translation
When free() is called on an invalid pointer, the program's memory management data structures may become corrupted. This corruption can cause the program to crash or, in some circumstances, an attacker may be able to cause free() to operate on controllable memory locations to modify critical program variables or execute code.
Technical Details
AI Translation
Common Consequences
integrity
confidentiality
availability
Impacts
execute unauthorized code or commands
modify memory
Detection Methods
fuzzing
automated static analysis
automated dynamic analysis
Potential Mitigations
Phases:
implementation
architecture and design
testing
Descriptions:
•
Only free pointers that you have called malloc on previously. This is the recommended solution. Keep track of which pointers point at the beginning of valid chunks and free them only once.
•
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
For example, glibc in Linux provides protection against free of invalid pointers.
•
Before freeing a pointer, the programmer should make sure that the pointer was previously allocated on the heap and that the memory belongs to the programmer. Freeing an unallocated pointer will cause undefined behavior in the program.
•
Use a language that provides abstractions for memory allocation and deallocation.
•
Use a tool that dynamically detects memory management problems, such as valgrind.
Functional Areas
memory management