CWE - CWE-1235: Incorrect Use of Autoboxing and Unboxing for Performance Critical Operations (4.18)

Home > CWE List > CWE-1235: Incorrect Use of Autoboxing and Unboxing for Performance Critical Operations (4.18)

CWE Glossary Definition

CWE-1235: Incorrect Use of Autoboxing and Unboxing for Performance Critical Operations

Weakness ID: 1235

Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.

View customized information:

For users who are interested in more notional aspects of a weakness. Example: educators, technical writers, and project/program managers. For users who are concerned with the practical application and details about the nature of a weakness and how to prevent it from happening. Example: tool developers, security researchers, pen-testers, incident response analysts. For users who are mapping an issue to CWE/CAPEC IDs, i.e., finding the most appropriate CWE for a specific issue (e.g., a CVE record). Example: tool developers, security researchers. For users who wish to see all available information for the CWE/CAPEC entry. For users who want to customize what details are displayed.

Edit Custom Filter

Description

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

Extended Description

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.

However, this feature comes at a cost of performance and can lead to resource exhaustion and impact availability when used with generic collections. Therefore, 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.

Common Consequences

Section HelpThis table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Impact	Details
DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other); Reduce Performance	Scope: Availability Likelihood: Low Incorrect autoboxing/unboxing would result in reduced performance, which sometimes can lead to resource consumption issues.

Potential Mitigations

Phase(s)	Mitigation
Implementation	Use of boxed primitives should be limited to certain situations such as when calling methods with typed parameters. Examine the use of boxed primitives prior to use. Use SparseArrays or ArrayMap instead of HashMap to avoid performance overhead.

Relationships

Section Help This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

Relevant to the view "Research Concepts" (View-1000)

Nature	Type	ID	Name
ChildOf	Class Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	400	Uncontrolled Resource Consumption

Relevant to the view "Software Development" (View-699)

Nature	Type	ID	Name
MemberOf	Category Category - a CWE entry that contains a set of other entries that share a common characteristic.	1006	Bad Coding Practices

Modes Of Introduction

Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

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

Applicable Platforms

Section HelpThis listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

Java (Undetermined Prevalence)

C# (Undetermined Prevalence)

Operating Systems

Class: Not OS-Specific (Undetermined Prevalence)

Architectures

Class: Not Architecture-Specific (Undetermined Prevalence)

Technologies

Class: Not Technology-Specific (Undetermined Prevalence)

Demonstrative Examples

Example 1

Java has a boxed primitive for each primitive type. A long can be represented with the boxed primitive Long. Issues arise where boxed primitives are used when not strictly necessary.

(bad code)

Example Language: Java

Long count = 0L;
for (long i = 0; i < Integer.MAX_VALUE; i++) {

count += i;

}

In the above loop, we see that the count variable is declared as a boxed primitive. This causes autoboxing on the line that increments. This causes execution to be magnitudes less performant (time and possibly space) than if the "long" primitive was used to declare the count variable, which can impact availability of a resource.

Example 2

This code uses primitive long which fixes the issue.

(good code)

Example Language: Java

long count = 0L;
for (long i = 0; i < Integer.MAX_VALUE; i++) {

count += i;

}

Memberships

Section HelpThis MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.

Nature	Type	ID	Name
MemberOf	CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage ALLOWED

(this CWE ID may be used to map to real-world vulnerabilities)

Reason Acceptable-Use

Rationale

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.

Comments

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.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
SEI CERT Oracle Coding Standard for Java	EXP04-J	Do not pass arguments to certain Java Collections Framework methods that are a different type than the collection parameter type
ISA/IEC 62443	Part 4-1	Req SI-2

References

[REF-1051] "Oracle Java Documentation".
<https://docs.oracle.com/javase/1.5.0/docs/guide/language/autoboxing.html>.

[REF-1052] The Software Engineering Institute. "SEI CERT Oracle Coding Standard for Java : Rule 02. Expressions (EXP)".
<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>.

Content History

Submissions
Submission Date	Submitter	Organization
2019年10月14日 (CWE 4.0, 2020年02月24日)	Joe Harvey
2019年10月14日 (CWE 4.0, 2020年02月24日)
Contributions
Contribution Date	Contributor	Organization
2023年04月25日	"Mapping CWE to 62443" Sub-Working Group	CWE-CAPEC ICS/OT SIG
2023年04月25日	Suggested mappings to ISA/IEC 62443.
Modifications
Modification Date	Modifier	Organization
2023年06月29日	CWE Content Team	MITRE
2023年06月29日	updated Mapping_Notes
2023年04月27日	CWE Content Team	MITRE
2023年04月27日	updated Relationships, Taxonomy_Mappings
2021年03月15日	CWE Content Team	MITRE
2021年03月15日	updated Demonstrative_Examples

More information is available — Please edit the custom filter or select a different filter.

Page Last Updated: September 09, 2025

MITRE

Use of the Common Weakness Enumeration (CWE™) and the associated references from this website are subject to the Terms of Use. CWE is sponsored by the U.S. Department of Homeland Security (DHS) Cybersecurity and Infrastructure Security Agency (CISA) and managed by the Homeland Security Systems Engineering and Development Institute (HSSEDI) which is operated by The MITRE Corporation (MITRE). Copyright © 2006–2025, The MITRE Corporation. CWE, CWSS, CWRAF, and the CWE logo are trademarks of The MITRE Corporation.

HSSEDI