CWE

Common Weakness Enumeration

A community-developed list of SW & HW weaknesses that can become vulnerabilities
New to CWE? click here!
CWE Most Important Hardware Weaknesses
CWE Top 25 Most Dangerous Weaknesses
Home > CWE List > CWE-543: Use of Singleton Pattern Without Synchronization in a Multithreaded Context (4.18)
ID
CWE Glossary Definition

CWE-543: Use of Singleton Pattern Without Synchronization in a Multithreaded Context

Weakness ID: 543
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.
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 product uses the singleton pattern when creating a resource within a multithreaded environment.
Extended Description
The use of a singleton pattern may not be thread-safe.
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

Other; Modify Application Data

Scope: Other, Integrity

Potential Mitigations
Phase(s) Mitigation

Architecture and Design
Use the Thread-Specific Storage Pattern. See References.

Implementation
Do not use member fields to store information in the Servlet. In multithreading environments, storing user data in Servlet member fields introduces a data access race condition.

Implementation
Avoid using the double-checked locking pattern in language versions that cannot guarantee thread safety. This pattern may be used to avoid the overhead of a synchronized call, but in certain versions of Java (for example), this has been shown to be unsafe because it still introduces a race condition (CWE-209).

Effectiveness: Limited
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
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
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)

Demonstrative Examples

Example 1


This method is part of a singleton pattern, yet the following singleton() pattern is not thread-safe. It is possible that the method will create two objects instead of only one.

(bad code)
Example Language: Java
private static NumberConverter singleton;
public static NumberConverter get_singleton() {
if (singleton == null) {
singleton = new NumberConverter();
}
return singleton;
}

Consider the following course of events:

  • Thread A enters the method, finds singleton to be null, begins the NumberConverter constructor, and then is swapped out of execution.
  • Thread B enters the method and finds that singleton remains null. This will happen if A was swapped out during the middle of the constructor, because the object reference is not set to point at the new object on the heap until the object is fully initialized.
  • Thread B continues and constructs another NumberConverter object and returns it while exiting the method.
  • Thread A continues, finishes constructing its NumberConverter object, and returns its version.

At this point, the threads have created and returned two different objects.



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. 861 The CERT Oracle Secure Coding Standard for Java (2011) Chapter 18 - Miscellaneous (MSC)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 986 SFP Secondary Cluster: Missing Lock
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
The CERT Oracle Secure Coding Standard for Java (2011) MSC07-J Prevent multiple instantiations of singleton objects
Software Fault Patterns SFP19 Missing Lock
References
[REF-474] Douglas C. Schmidt, Timothy H. Harrison and Nat Pryce. "Thread-Specifc Storage for C/C++".
<https://www.dre.vanderbilt.edu/~schmidt/PDF/TSS-pattern.pdf>. (URL validated: 2025年07月24日)
Content History
Submissions
Submission Date Submitter Organization
2006年07月19日
(CWE Draft 3, 2006年07月19日) 		Anonymous Tool Vendor (under NDA)
Modifications
Modification Date Modifier Organization
2025年09月09日
(CWE 4.18, 2025年09月09日) 		CWE Content Team MITRE
updated References
2023年06月29日 CWE Content Team MITRE
updated Mapping_Notes
2023年04月27日 CWE Content Team MITRE
updated Relationships
2023年01月31日 CWE Content Team MITRE
updated Description
2020年12月10日 CWE Content Team MITRE
updated Relationships
2020年08月20日 CWE Content Team MITRE
updated Relationships
2020年02月24日 CWE Content Team MITRE
updated Relationships
2019年01月03日 CWE Content Team MITRE
updated Taxonomy_Mappings
2014年07月30日 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2012年05月11日 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2011年06月01日 CWE Content Team MITRE
updated Common_Consequences, Relationships, Taxonomy_Mappings
2011年03月29日 CWE Content Team MITRE
updated Demonstrative_Examples
2010年12月13日 CWE Content Team MITRE
updated Applicable_Platforms, Demonstrative_Examples, Description, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2010年09月27日 CWE Content Team MITRE
updated Name
2008年09月08日 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2008年07月01日 Eric Dalci Cigital
updated Potential_Mitigations, Time_of_Introduction
Previous Entry Names
Change Date Previous Entry Name
2010年09月27日 Use of Singleton Pattern in a Non-thread-safe Manner
More information is available — Please edit the custom filter or select a different filter.
Page Last Updated: September 09, 2025

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.

AltStyle によって変換されたページ (->オリジナル) /