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

Code Examples & CVEs

Demonstrative Examples

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.

Consider the following course of events:

BadJava

private static NumberConverter singleton;public static NumberConverter get_singleton() {if (singleton == null) {singleton = new NumberConverter();}return singleton;}

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-543 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-543, Use of Singleton Pattern Without Synchronization in a Multithreaded Context, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Use of Singleton Pattern Without Synchronization in a Multithreaded Context during Architecture and Design

MITRE associates mitigation with Architecture and Design, and Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include Other, and Modify Application Data. Use these source-defined anchors to turn CWE-543 into implementation, review, and verification checks for the affected component.

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

Triage CWE-543 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-543, Use of Singleton Pattern Without Synchronization in a Multithreaded Context, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-543

Apply MITRE's full root-cause mapping guidance when using CWE-543, Use of Singleton Pattern Without Synchronization in a Multithreaded Context. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-543 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-543, Use of Singleton Pattern Without Synchronization in a Multithreaded Context. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-543: Use of Singleton Pattern Without Synchronization in a Multithreaded Context?+

CWE-543: Use of Singleton Pattern Without Synchronization in a Multithreaded Context is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product uses the singleton pattern when creating a resource within a multithreaded environment. The use of a singleton pattern may not be thread-safe.

What are the security consequences of Use of Singleton Pattern Without Synchronization in a Multithreaded Context?+

If exploited, CWE-543 (Use of Singleton Pattern Without Synchronization in a Multithreaded Context) it can compromise Other and Integrity, leading to outcomes such as Other and Modify Application Data.

How do you prevent or mitigate Use of Singleton Pattern Without Synchronization in a Multithreaded Context?+

Recommended mitigations for CWE-543 include: Use the Thread-Specific Storage Pattern. See References. 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. 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).

Which programming languages are affected by Use of Singleton Pattern Without Synchronization in a Multithreaded Context?+

CWE-543 commonly affects Java and C++. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-543 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

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

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Phase

Description

Phase

Description

Phase

Description

Effectiveness

Detection Methods

Code Examples & CVEs

Demonstrative Examples

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-543 with SSDF evidence

Address Use of Singleton Pattern Without Synchronization in a Multithreaded Context during Architecture and Design

Triage CWE-543 against known exploitation evidence

Apply precise root-cause mapping to CWE-543

Validate CWE-543 with root-cause mapping checks

Frequently Asked Questions

Learn More