CWE - CWE-1096: Singleton Class Instance Creation without Proper Locking or Synchronization (4.18)

Home > CWE List > CWE-1096: Singleton Class Instance Creation without Proper Locking or Synchronization (4.18)

CWE Glossary Definition

CWE-1096: Singleton Class Instance Creation without Proper Locking or Synchronization

Weakness ID: 1096

Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.

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Description

The product implements a Singleton design pattern but does not use appropriate locking or other synchronization mechanism to ensure that the singleton class is only instantiated once.

Extended Description

This issue can prevent the product from running reliably, e.g. by making the instantiation process non-thread-safe and introducing deadlock (CWE-833) or livelock conditions. If the relevant code is reachable by an attacker, then this reliability problem might introduce a vulnerability.

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
Reduce Reliability	Scope: Other

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	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.	820	Missing Synchronization

Relevant to the view "CISQ Quality Measures (2020)" (View-1305)

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.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (View-1340)

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.	662	Improper Synchronization

Weakness Ordinalities

Ordinality	Description
Indirect	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect)

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.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

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 Variant 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
OMG ASCRM	ASCRM-RLB-12

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-RLB-12. 2016-01.
<http://www.omg.org/spec/ASCRM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2018年07月02日 (CWE 3.2, 2019年01月03日)	CWE Content Team	MITRE
2018年07月02日 (CWE 3.2, 2019年01月03日)	Entry derived from Common Quality Enumeration (CQE) Draft 0.9.
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
2023年01月31日	CWE Content Team	MITRE
2023年01月31日	updated Description
2020年12月10日	CWE Content Team	MITRE
2020年12月10日	updated Relationships
2020年08月20日	CWE Content Team	MITRE
2020年08月20日	updated Relationships
2020年02月24日	CWE Content Team	MITRE
2020年02月24日	updated Description, Relationships

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Page Last Updated: September 09, 2025

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