CWE-761
Free of Pointer not at Start of Buffer
AI Translation Available
The product calls free() on a pointer to a memory resource that was allocated on the heap, but the pointer is not at the start of the buffer.
Status
incomplete
Abstraction
variant
Affected Platforms
C
Memory-Unsafe
Extended Description
AI Translation
This can cause the product to crash, or in some cases, modify critical program variables or execute code.
This weakness often occurs when the memory is allocated explicitly on the heap with one of the malloc() family functions and free() is called, but pointer arithmetic has caused the pointer to be in the interior or end of the buffer.
Technical Details
AI Translation
Common Consequences
integrity
availability
confidentiality
Impacts
modify memory
dos: crash, exit, or restart
execute unauthorized code or commands
Detection Methods
dynamic analysis with automated results interpretation
automated dynamic analysis
Potential Mitigations
Phases:
implementation
architecture and design
Descriptions:
•
When utilizing pointer arithmetic to traverse a buffer, use a separate variable to track progress through memory and preserve the originally allocated address for later freeing.
•
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.
•
When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.
•
Use a language that provides abstractions for memory allocation and deallocation.
Functional Areas
memory management