The product omits a break statement within a switch or similar construct, causing code associated with multiple conditions to execute. This can cause problems when the programmer only intended to execute code associated with one condition.
This can lead to critical code executing in situations where it should not.

Primary

Indirect

Implementation

Medium

Other
Alter Execution Logic
This weakness can cause unintended logic to be executed and other unexpected application behavior.

White Box
Omission of a break statement might be intentional, in order to support fallthrough. Automated detection methods might therefore be erroneous. Semantic understanding of expected product behavior is required to interpret whether the code is correct.

Black Box
Since this weakness is associated with a code construct, it would be indistinguishable from other errors that produce the same behavior.

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.)
High

Implementation
Omitting a break statement so that one may fall through is often indistinguishable from an error, and therefore should be avoided. If you need to use fall-through capabilities, make sure that you have clearly documented this within the switch statement, and ensure that you have examined all the logical possibilities.

Implementation
The functionality of omitting a break statement could be clarified with an if statement. This method is much safer.

In both of these examples, a message is printed based on the month passed into the function:

public void printMessage(int month){
switch (month) {

case 1: print("January");case 2: print("February");case 3: print("March");case 4: print("April");case 5: print("May");case 6: print("June");case 7: print("July");case 8: print("August");case 9: print("September");case 10: print("October");case 11: print("November");case 12: print("December");
}println(" is a great month");
}

void printMessage(int month){
switch (month) {

case 1: printf("January");case 2: printf("February");case 3: printf("March");case 4: printf("April");case 5: printff("May");case 6: printf("June");case 7: printf("July");case 8: printf("August");case 9: printf("September");case 10: printf("October");case 11: printf("November");case 12: printf("December");
}printf(" is a great month");
}

Both examples do not use a break statement after each case, which leads to unintended fall-through behavior. For example, calling "printMessage(10)" will result in the text "OctoberNovemberDecember is a great month" being printed.

Omitted break statement

SFP4
Unchecked Status Condition

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.

CLASP
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Applicable_Platforms, Description, Detection_Factors, Relationships, Other_Notes, Taxonomy_Mappings

CWE Content Team
MITRE
2008-11-24
updated Applicable_Platforms, Demonstrative_Examples, Description, Detection_Factors, Name, Other_Notes, Potential_Mitigations, Weakness_Ordinalities

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2012-05-11
updated Common_Consequences, References, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2012-10-30
updated Demonstrative_Examples

CWE Content Team
MITRE
2014-07-30
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2017-11-08
updated Demonstrative_Examples, Relationships

CWE Content Team
MITRE
2019-01-03
updated Weakness_Ordinalities

CWE Content Team
MITRE
2020-02-24
updated References, Relationships

CWE Content Team
MITRE
2020-08-20
updated Relationships

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

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

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2023-10-26
updated Demonstrative_Examples

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Applicable_Platforms, Relationships

Omitted Break Statement