Common Weakness Enumeration

CWE-581

Weakness Allowed

Object Model Violation: Just One of Equals and Hashcode Defined

Abstraction: Variant · Status: Draft

API response cwe.mitre.org

The product does not maintain equal hashcodes for equal objects.

Mapping guidance

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.

Relationships and members
ChildOf: CWE-573 · View CWE-1000
ChildOf: CWE-697 · View CWE-1000
Modes of introduction
Implementation
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.)

Effectiveness: High

Content history
Submission: CWE Community · 2006-12-15 · CWE Draft 5

Submitted by members of the CWE community to extend early CWE versions

Modification: Eric Dalci · Cigital · 2008-07-01 · CWE 1.0

updated Potential_Mitigations, Time_of_Introduction

Modification: CWE Content Team · MITRE · 2008-09-08 · CWE 1.0

updated Common_Consequences, Relationships, Other_Notes

Modification: CWE Content Team · MITRE · 2009-10-29 · CWE 1.6

updated Common_Consequences, Description, Other_Notes

Modification: CWE Content Team · MITRE · 2010-12-13 · CWE 1.11

updated Common_Consequences

Modification: CWE Content Team · MITRE · 2011-03-29 · CWE 1.12

updated Description

Modification: CWE Content Team · MITRE · 2011-06-01 · CWE 1.13

updated Common_Consequences, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2012-05-11 · CWE 2.2

updated Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2012-10-30 · CWE 2.3

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2014-07-30 · CWE 2.8

updated Relationships

Modification: CWE Content Team · MITRE · 2018-03-27 · CWE 3.1

updated Relationships

Modification: CWE Content Team · MITRE · 2019-01-03 · CWE 3.2

updated Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2020-02-24 · CWE 4.0

updated Relationships

Modification: CWE Content Team · MITRE · 2023-01-31 · CWE 4.10

updated Description

Modification: CWE Content Team · MITRE · 2023-04-27 · CWE 4.11

updated Detection_Factors, Relationships

Modification: CWE Content Team · MITRE · 2023-06-29 · CWE 4.12

updated Mapping_Notes

Modification: CWE Content Team · MITRE · 2024-02-29 · CWE 4.14

updated Type

Modification: CWE Content Team · MITRE · 2025-12-11 · CWE 4.19

updated Weakness_Ordinalities

Modification: CWE Content Team · MITRE · 2026-10-28 · CWE 5.0

updated Background_Details, Description

0 vulnerabilities reference this CWE, most recent first.

No vulnerabilities reference this CWE.

Mitigation
Implementation

Both Equals() and Hashcode() should be defined.

No CAPEC attack patterns related to this CWE.

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