The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
When a product releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the product to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.

Resultant

Dangling pointer

Implementation

Confidentiality
Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.

Availability
DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.

Integrity
Confidentiality
Availability
Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.

Automated Static Analysis
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Automated Dynamic Analysis
Use tools that are integrated during
compilation to insert runtime error-checking mechanisms
related to memory safety errors, such as AddressSanitizer
(ASan) for C/C++ [REF-1518].
Moderate
Crafted inputs are necessary to
reach the code containing the error, such as generated
by fuzzers. Also, these tools may reduce performance,
and they only report the error condition - not the
original mistake that led to the
error.

Architecture and Design
Choose a language that provides automatic memory management.

Implementation
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

The following code shows a simple example of a use after free error:

char* ptr = (char*)malloc (SIZE);if (err) {abrt = 1;free(ptr);}...if (abrt) {logError("operation aborted before commit", ptr);}

When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.

The following code shows a simple example of a double free error:

char* ptr = (char*)malloc (SIZE);...if (abrt) {free(ptr);}...free(ptr);

Double free vulnerabilities have two common (and sometimes overlapping) causes:

Error conditions and other exceptional circumstances

Confusion over which part of the program is responsible for freeing the memory

Although some double free vulnerabilities are not much more complicated than the previous example, most are spread out across hundreds of lines of code or even different files. Programmers seem particularly susceptible to freeing global variables more than once.

CVE-2023-26463
Chain: IPSec VPN product uses the same variable for multiple purposes in the same function (CWE-1109), leading to incorrect access control (CWE-284) and expired pointer dereference (CWE-825)
https://www.cve.org/CVERecord?id=CVE-2023-26463

CVE-2008-5013
access of expired memory address leads to arbitrary code execution
https://www.cve.org/CVERecord?id=CVE-2008-5013

CVE-2010-3257
stale pointer issue leads to denial of service and possibly other consequences
https://www.cve.org/CVERecord?id=CVE-2010-3257

CVE-2008-0062
Chain: a message having an unknown message type may cause a reference to uninitialized memory resulting in a null pointer dereference (CWE-476) or dangling pointer (CWE-825), possibly crashing the system or causing heap corruption.
https://www.cve.org/CVERecord?id=CVE-2008-0062

CVE-2007-1211
read of value at an offset into a structure after the offset is no longer valid
https://www.cve.org/CVERecord?id=CVE-2007-1211

Memory Management

Memory

Allowed
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

There are close relationships between incorrect pointer dereferences and other weaknesses related to buffer operations. There may not be sufficient community agreement regarding these relationships. Further study is needed to determine when these relationships are chains, composites, perspective/layering, or other types of relationships. As of September 2010, most of the relationships are being captured as chains.
Many weaknesses related to pointer dereferences fall under the general term of "memory corruption" or "memory safety." As of September 2010, there is no commonly-used terminology that covers the lower-level variants.

CWE Content Team
MITRE
2010-09-22
1.10
2010-09-27

CWE Content Team
MITRE
2011-06-27
updated Demonstrative_Examples, Potential_Mitigations, Relationships

CWE Content Team
MITRE
2012-05-11
updated Demonstrative_Examples, Relationships

CWE Content Team
MITRE
2013-02-21
updated Alternate_Terms

CWE Content Team
MITRE
2020-02-24
updated Relationships

CWE Content Team
MITRE
2020-08-20
updated Relationships

CWE Content Team
MITRE
2020-12-10
updated Relationships

CWE Content Team
MITRE
2021-03-15
updated Observed_Examples

CWE Content Team
MITRE
2022-04-28
updated Research_Gaps

CWE Content Team
MITRE
2023-01-31
updated Common_Consequences, Description

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2025-04-03
4.17
2025-04-03
updated Applicable_Platforms

CWE Content Team
MITRE
2025-09-09
4.18
2025-09-09
updated Affected_Resources, Functional_Areas

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Applicable_Platforms, Detection_Factors, Observed_Examples, References, Time_of_Introduction, Weakness_Ordinalities