The product uses multiple resources that can have the same identifier, in a context in which unique identifiers are required.
If the product assumes that each resource has a unique identifier, the product could operate on the wrong resource if attackers can cause multiple resources to be associated with the same identifier.

Primary

Resultant

Architecture and Design

Implementation

Access Control
Bypass Protection Mechanism
If unique identifiers are assumed when protecting sensitive resources, then duplicate identifiers might allow attackers to bypass the protection.

Other
Quality Degradation

Architecture and Design
Where possible, use unique identifiers. If non-unique identifiers are detected, then do not operate any resource with a non-unique identifier and report the error appropriately.

These two Struts validation forms have the same name.

<form-validation>

<formset>

<form name="ProjectForm"> ... </form>
<form name="ProjectForm"> ... </form>

</formset>

</form-validation>

It is not certain which form will be used by Struts. It is critically important that validation logic be maintained and kept in sync with the rest of the product.

CVE-2013-4787
chain: mobile OS verifies cryptographic signature of file in an archive, but then installs a different file with the same name that is also listed in the archive.
https://www.cve.org/CVERecord?id=CVE-2013-4787

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.

This weakness is probably closely associated with other issues related to doubling, such as CWE-675 (Duplicate Operations on Resource). It's often a case of an API contract violation (CWE-227).

CWE Content Team
MITRE
2008-09-09
1.0
2008-09-09
Note: this date reflects when the entry was first published. Draft versions of this entry were provided to members of the CWE community and modified between Draft 9 and 1.0.

Eric Dalci
Cigital
2008-07-01
updated Potential_Mitigations, Time_of_Introduction

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences

CWE Content Team
MITRE
2011-06-27
updated Common_Consequences

CWE Content Team
MITRE
2012-05-11
updated Relationships

CWE Content Team
MITRE
2012-10-30
updated Potential_Mitigations

CWE Content Team
MITRE
2013-07-17
updated Applicable_Platforms, Common_Consequences, Description, Observed_Examples, Other_Notes, Potential_Mitigations, Relationship_Notes, Relationships

CWE Content Team
MITRE
2014-07-30
updated Relationships

CWE Content Team
MITRE
2015-12-07
updated Relationships

CWE Content Team
MITRE
2017-11-08
updated Relevant_Properties

CWE Content Team
MITRE
2019-06-20
updated Relationships

CWE Content Team
MITRE
2020-02-24
updated Relationships

CWE Content Team
MITRE
2023-01-31
updated Description

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2024-02-29
4.14
2024-02-29
updated Demonstrative_Examples

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Weakness_Ordinalities