Assignment to Variable without Use

The variable's value is assigned but never used, making it a dead store.


After the assignment, the variable is either assigned another value or goes out of scope. It is likely that the variable is simply vestigial, but it is also possible that the unused variable points out a bug.


The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following code excerpt assigns to the variable r and then overwrites the value without using it.

r = getName();
r = getNewBuffer(buf);

See Also

SEI CERT Perl Coding Standard - Guidelines 50. Miscellaneous (MSC)

Weaknesses in this category are related to the rules and recommendations in the Miscellaneous (MSC) section of the SEI CERT Perl Coding Standard.

Bad Coding Practices

Weaknesses in this category are related to coding practices that are deemed unsafe and increase the chances that an exploitable vulnerability will be present in the ap...

SFP Primary Cluster: Unused entities

This category identifies Software Fault Patterns (SFPs) within the Unused entities cluster (SFP2).

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Quality Weaknesses with Indirect Security Impacts

CWE identifiers in this view (slice) are quality issues that only indirectly make it easier to introduce a vulnerability and/or make the vulnerability more difficult t...

CWE Cross-section

This view contains a selection of weaknesses that represent the variety of weaknesses that are captured in CWE, at a level of abstraction that is likely to be useful t...

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