CWE-1235 Detail

CWE-1235

Incorrect Use of Autoboxing and Unboxing for Performance Critical Operations
Incomplete
2020-02-24
00h00 +00:00
2025-12-11
00h00 +00:00
Notifications for a CWE
Stay informed of any changes for a specific CWE.
Notifications manage

Name: Incorrect Use of Autoboxing and Unboxing for Performance Critical Operations

The code uses boxed primitives, which may introduce inefficiencies into performance-critical operations.

General Informations

Background Details

Languages such as Java and C# support automatic conversion through their respective compilers from primitive types into objects of the corresponding wrapper classes, and vice versa. For example, a compiler might convert an int to Integer (called autoboxing) or an Integer to int (called unboxing). This eliminates forcing the programmer to perform these conversions manually, which makes the code cleaner.

Modes Of Introduction

Implementation : The programmer may use boxed primitives when not strictly necessary.

Applicable Platforms

Language

Name: Java (Undetermined)
Name: C# (Undetermined)

Operating Systems

Class: Not OS-Specific (Undetermined)

Architectures

Class: Not Architecture-Specific (Undetermined)

Technologies

Class: Not Technology-Specific (Undetermined)

Common Consequences

Scope Impact Likelihood
AvailabilityDoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Resource Consumption (Other), Reduce Performance

Note: Incorrect autoboxing/unboxing would result in reduced performance, which sometimes can lead to resource consumption issues, impacting availability when used with generic collections.
Low

Potential Mitigations

Phases : Implementation
Use of boxed primitives should be limited to certain situations such as when calling methods with typed parameters. They should not be used for scientific computing or other performance critical operations. They are only suited to support "impedance mismatch" between reference types and primitives. Examine the use of boxed primitives prior to use. Use SparseArrays or ArrayMap instead of HashMap to avoid performance overhead.

Detection Methods

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.)

Vulnerability Mapping Notes

Justification : 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.
Comment : 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.

References

REF-1051

Oracle Java Documentation
https://docs.oracle.com/javase/1.5.0/docs/guide/language/autoboxing.html

REF-1052

SEI CERT Oracle Coding Standard for Java : Rule 02. Expressions (EXP)
The Software Engineering Institute.
https://wiki.sei.cmu.edu/confluence/display/java/EXP04-J.+Do+not+pass+arguments+to+certain+Java+Collections+Framework+methods+that+are+a+different+type+than+the+collection+parameter+type

Submission

Name Organization Date Date release Version
Joe Harvey 2019-10-14 +00:00 2020-02-24 +00:00 4.0

Modifications

Name Organization Date Comment
CWE Content Team MITRE 2021-03-15 +00:00 updated Demonstrative_Examples
CWE Content Team MITRE 2023-04-27 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2025-12-11 +00:00 updated Background_Details, Common_Consequences, Description, Detection_Factors, Potential_Mitigations, Weakness_Ordinalities