An interaction error occurs when two entities have correct behavior when running independently of each other, but when they are integrated as components in a larger system or process, they introduce incorrect behaviors that may cause resultant weaknesses.
When a system or process combines multiple independent components, this often produces new, emergent behaviors at the system level. However, if the interactions between these components are not fully accounted for, some of the emergent behaviors can be incorrect or even insecure.

Primary

Interaction Error

Emergent Fault

Architecture and Design

Implementation

Operation

Integrity
Unexpected State
Varies by Context

The paper "Insertion, Evasion, and Denial of Service: Eluding Network Intrusion Detection" [REF-428] shows that OSes varied widely in how they manage unusual packets, which made it difficult or impossible for intrusion detection systems to properly detect certain attacker manipulations that took advantage of these OS differences.

CVE-2002-0485
Anti-virus product allows bypass via Content-Type and Content-Disposition headers that are mixed case, which are still processed by some clients.
https://www.cve.org/CVERecord?id=CVE-2002-0485

CVE-2003-0411
chain: Code was ported from a case-sensitive Unix platform to a case-insensitive Windows platform where filetype handlers treat .jsp and .JSP as different extensions. JSP source code may be read because .JSP defaults to the filetype "text".
https://www.cve.org/CVERecord?id=CVE-2003-0411

Interaction Errors

Discouraged
This CWE entry is extremely high-level, a Pillar. However, sometimes this weakness is forced to be used due to the lack of in-depth weakness research. See Research Gaps.
Where feasible, consider children or descendants of this entry instead.

Weaknesses related to this Pillar appear to be under-studied, especially with respect to classification schemes. Input from academic and other communities could help identify and resolve gaps or organizational difficulties within CWE.

The "Interaction Error" term, in CWE and elsewhere, is only intended to describe products that behave according to specification. When one or more of the products do not comply with specifications, then it is more likely to be API Abuse (CWE-227) or an interpretation conflict (CWE-436). This distinction can be blurred in real world scenarios, especially when "de facto" standards do not comply with specifications, or when there are no standards but there is widespread adoption. As a result, it can be difficult to distinguish these weaknesses during mapping and classification.

PLOVER
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Relationships, Relationship_Notes, Taxonomy_Mappings

CWE Content Team
MITRE
2008-10-14
updated Description, Relationships

CWE Content Team
MITRE
2008-11-24
updated Relationships

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
2014-07-30
updated Relationships

CWE Content Team
MITRE
2015-12-07
updated Relationships

CWE Content Team
MITRE
2017-01-19
updated Relationships

CWE Content Team
MITRE
2017-11-08
updated Applicable_Platforms, Name, Relationships

CWE Content Team
MITRE
2018-03-27
updated Alternate_Terms, Description, Name, References, Relationships

CWE Content Team
MITRE
2019-06-20
updated Relationships

CWE Content Team
MITRE
2020-02-24
updated Applicable_Platforms, Type

CWE Content Team
MITRE
2023-04-27
updated References, Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes, Research_Gaps

CWE Content Team
MITRE
2023-10-26
updated Observed_Examples

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

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

Interaction Errors
Interaction Error
Improper Interaction Between Multiple Entities