The product has multiple functions, methods, procedures, macros, etc. that
contain the same code.

Indirect

Implementation

Other
Reduce Maintainability
This issue makes it more difficult to maintain the product, which indirectly affects security by making it more difficult or time-consuming to find and/or fix vulnerabilities. For example, if there are two copies of the same code, the programmer might fix a weakness in one copy while forgetting to fix the same weakness in another copy.

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.)

Implementation
Merge common functionality into a single function and then call that function from across the entire code base.

In the following Java example the code performs some complex math when specific test conditions are met. The math is the same in each case and the equations are repeated within the code. Unfortunately if a future change needs to be made then that change needs to be made in all locations. This opens the door to mistakes being made and the changes not being made in the same way in each instance.

public class Main {
public static void main(String[] args) {
double s = 10.0;
double r = 1.0;
double pi = 3.14159;
double surface_area;
if(r > 0.0) {
// complex math equations
surface_area = pi * r * s + pi * Math.pow(r, 2);
}
if(r > 1.0) {
// a complex set of math
surface_area = pi * r * s + pi * Math.pow(r, 2);
}
}
}

It is recommended to place the complex math into its own function and then call that function whenever necessary.

public class Main {
private double ComplexMath(double r, double s) {
//complex math equations
double pi = Math.PI;
double surface_area = pi * r * s + pi * Math.pow(r, 2);
return surface_area;
}
public static void main(String[] args) {
double s = 10.0;
double r = 1.0;
double surface_area;
if(r > 0.0) {
surface_area = ComplexMath(r, s);
}
if(r > 1.0) {
surface_area = ComplexMath(r, s);
}
}
}

ASCMM-MNT-19

Prohibited
This entry is primarily a quality issue with no direct security implications.
Look for weaknesses that are focused specifically on insecure behaviors that have more direct security implications.

CWE Content Team
MITRE
2018-07-02
3.2
2019-01-03
Entry derived from Common Quality Enumeration (CQE) Draft 0.9.

CWE Content Team
MITRE
2020-08-20
updated Relationships

CWE Content Team
MITRE
2022-10-13
updated Applicable_Platforms, Demonstrative_Examples, Potential_Mitigations

CWE Content Team
MITRE
2023-01-31
updated Description

CWE Content Team
MITRE
2023-04-27
updated References, Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2024-02-29
4.14
2024-02-29
updated Mapping_Notes

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Common_Consequences, Description, Detection_Factors, Time_of_Introduction

Drew Buttner
MITRE
2022-08-15
Suggested new demonstrative examples, mitigations, and applicable platforms.