CWE-762: Mismatched Memory Management Routines

Extended Description

This weakness can be generally described as mismatching memory management routines, such as: The memory was allocated on the stack (automatically), but it was deallocated using the memory management routine free() (CWE-590), which is intended for explicitly allocated heap memory. The memory was allocated explicitly using one set of memory management functions, and deallocated using a different set. For example, memory might be allocated with malloc() in C++ instead of the new operator, and then deallocated with the delete operator. When the memory management functions are mismatched, the consequences may be as severe as code execution, memory corruption, or program crash. Consequences and ease of exploit will vary depending on the implementation of the routines and the object being managed.

Code Examples & CVEs

Demonstrative Examples

This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.

Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.

BadC++

void foo(){                         BarObj *ptr = new BarObj()                            /* do some work with ptr here */                                                        ...                            free(ptr);                      }

This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.

Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.

GoodC++

void foo(){                         BarObj *ptr = new BarObj()                            /* do some work with ptr here */                                                        ...                            delete ptr;                      }

In this example, the program does not use matching functions such as malloc/free, new/delete, and new[]/delete[] to allocate/deallocate the resource.

BadC++

class A {void foo();};void A::foo(){int *ptr;ptr = (int*)malloc(sizeof(int));delete ptr;}

In this example, the program calls the delete[] function on non-heap memory.

BadC++

class A{void foo(bool);};void A::foo(bool heap) {int localArray[2] = {11,22};int *p = localArray;if (heap){p = new int[2];}delete[] p;}

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-762 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-762, Mismatched Memory Management Routines, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Apply Libraries or Frameworks controls for Mismatched Memory Management Routines

MITRE associates mitigation with Implementation, and Architecture and Design; the listed strategies include Libraries or Frameworks; documented detection approaches include Automated Dynamic Analysis. Use these source-defined anchors to turn CWE-762 into implementation, review, and verification checks for the affected component.

CWE-762: Mismatched Memory Management Routines — MITRE CWE

Triage CWE-762 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-762, Mismatched Memory Management Routines, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-762

Apply MITRE's full root-cause mapping guidance when using CWE-762, Mismatched Memory Management Routines. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-762 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-762, Mismatched Memory Management Routines. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-762: Mismatched Memory Management Routines?+

CWE-762: Mismatched Memory Management Routines is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product attempts to return a memory resource to the system, but it calls a release function that is not compatible with the function that was originally used to allocate that resource. This weakness can be generally described as mismatching memory management routines, such as: The memory was allocated on the stack (automatically), but it was deallocated using the memory management routine free() (CWE-590), which is intended for explicitly allocated heap memory. The memory was allocated explicitly using one set of memory management functions, and deallocated using a different set. For example, memory might be allocated with malloc() in C++ instead of the new operator, and then deallocated with the delete operator. When the memory management functions are mismatched, the consequences may be as severe as code execution, memory corruption, or program crash. Consequences and ease of exploit will vary depending on the implementation of the routines and the object being managed.

What are the security consequences of Mismatched Memory Management Routines?+

If exploited, CWE-762 (Mismatched Memory Management Routines) it can compromise Integrity, Availability and Confidentiality, leading to outcomes such as Modify Memory, DoS: Crash, Exit, or Restart and Execute Unauthorized Code or Commands.

How do you prevent or mitigate Mismatched Memory Management Routines?+

Recommended mitigations for CWE-762 include: Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free(). Use a language that provides abstractions for memory allocation and deallocation.

Which programming languages are affected by Mismatched Memory Management Routines?+

CWE-762 commonly affects C, C++ and Memory-Unsafe. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-762 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.

CWE-762: Mismatched Memory Management Routines

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Phase

Description

Phase

Description

Detection Methods

Code Examples & CVEs

Demonstrative Examples

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-762 with SSDF evidence

Apply Libraries or Frameworks controls for Mismatched Memory Management Routines

Triage CWE-762 against known exploitation evidence

Apply precise root-cause mapping to CWE-762

Validate CWE-762 with root-cause mapping checks

Frequently Asked Questions

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