The product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().
View on MITREWhen 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.
There is the potential for arbitrary code execution with privileges of the vulnerable program via a "write, what where" primitive. If pointers to memory which hold user information are freed, a malicious user will be able to write 4 bytes anywhere in memory.
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.
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.
No detection method information available for this CWE.
In this example, an array of record_t structs, bar, is allocated automatically on the stack as a local variable and the programmer attempts to call free() on the array. The consequences will vary based on the implementation of free(), but it will not succeed in deallocating the memory.
This example shows the array allocated globally, as part of the data segment of memory and the programmer attempts to call free() on the array.
In this example, an array of record_t structs, bar, is allocated automatically on the stack as a local variable and the programmer attempts to call free() on the array. The consequences will vary based on the implementation of free(), but it will not succeed in deallocating the memory.
This example shows the array allocated globally, as part of the data segment of memory and the programmer attempts to call free() on the array.
In this example, an array of record_t structs, bar, is allocated automatically on the stack as a local variable and the programmer attempts to call free() on the array. The consequences will vary based on the implementation of free(), but it will not succeed in deallocating the memory.
This example shows the array allocated globally, as part of the data segment of memory and the programmer attempts to call free() on the array.
In this example, an array of record_t structs, bar, is allocated automatically on the stack as a local variable and the programmer attempts to call free() on the array. The consequences will vary based on the implementation of free(), but it will not succeed in deallocating the memory.
This example shows the array allocated globally, as part of the data segment of memory and the programmer attempts to call free() on the array.
No relationship information available for this CWE.
CWE-590: Free of Memory not on the Heap is a Common Weakness Enumeration (CWE) entry maintained by MITRE. 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.
If exploited, CWE-590 (Free of Memory not on the Heap) it can compromise Integrity, Confidentiality and Availability, leading to outcomes such as Execute Unauthorized Code or Commands and Modify Memory.
Recommended mitigations for CWE-590 include: 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. 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.
A CWE (Common Weakness Enumeration) like CWE-590 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.