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CWE-590

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CWE-590

Free of Memory not on the Heap

Variant
Incomplete

Description

The product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().

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.

Related Weaknesses

Common Consequences

Scope

Integrity
Confidentiality
Availability

Impact

Execute Unauthorized Code or Commands, Modify Memory

Potential Mitigations

Implementation

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.

Implementation

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.

Architecture and Design

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.

Architecture and Design

Use a language that provides abstractions for memory allocation and deallocation.

CVE-2023-22291

parser for a word processor attempts to free a stack pointer when intending to expand memory to hold a larger buffer

Applicable Platforms

Memory-Unsafe
C

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