CWE-585: Empty Synchronized Block

Code Examples & CVEs

Demonstrative Examples

The following code attempts to synchronize on an object, but does not execute anything in the synchronized block. This does not actually accomplish anything and may be a sign that a programmer is wrestling with synchronization but has not yet achieved the result they intend.

Instead, in a correct usage, the synchronized statement should contain procedures that access or modify data that is exposed to multiple threads. For example, consider a scenario in which several threads are accessing student records at the same time. The method which sets the student ID to a new value will need to make sure that nobody else is accessing this data at the same time and will require synchronization.

BadJava

synchronized(this) { }

GoodJava

public void setID(int ID){synchronized(this){this.ID = ID;}}

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-585 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-585, Empty Synchronized Block, 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 Empty Synchronized Block during Implementation

MITRE associates mitigation with Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include Other. Use these source-defined anchors to turn CWE-585 into implementation, review, and verification checks for the affected component.

CWE-585: Empty Synchronized Block — MITRE CWE

Triage CWE-585 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-585, Empty Synchronized Block, 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-585

Apply MITRE's full root-cause mapping guidance when using CWE-585, Empty Synchronized Block. 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-585 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-585, Empty Synchronized Block. 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-585: Empty Synchronized Block?+

CWE-585: Empty Synchronized Block is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product contains an empty synchronized block. An empty synchronized block does not actually accomplish any synchronization and may indicate a troubled section of code. An empty synchronized block can occur because code no longer needed within the synchronized block is commented out without removing the synchronized block.

What are the security consequences of Empty Synchronized Block?+

If exploited, CWE-585 (Empty Synchronized Block) it can compromise Other, leading to outcomes such as Other.

How do you prevent or mitigate Empty Synchronized Block?+

Recommended mitigations for CWE-585 include: When you come across an empty synchronized statement, or a synchronized statement in which the code has been commented out, try to determine what the original intentions were and whether or not the synchronized block is still necessary.

Which programming languages are affected by Empty Synchronized Block?+

CWE-585 commonly affects Java. 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-585 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-585: Empty Synchronized Block

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