CWE-764: Multiple Locks of a Critical Resource

Extended Description

When a product is operating in a concurrent environment and repeatedly locks a critical resource, the consequences will vary based on the type of lock, the lock's implementation, and the resource being protected. In some situations such as with semaphores, the resources are pooled and extra locking calls will reduce the size of the total available pool, possibly leading to degraded performance or a denial of service. If this can be triggered by an attacker, it will be similar to an unrestricted lock (CWE-412). In the context of a binary lock, it is likely that any duplicate locking attempts will never succeed since the lock is already held and progress may not be possible.

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-764 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-764, Multiple Locks of a Critical Resource, 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 Multiple Locks of a Critical Resource during Implementation

MITRE associates mitigation with Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include DoS: Resource Consumption (CPU), DoS: Crash, Exit, or Restart, and Unexpected State. Use these source-defined anchors to turn CWE-764 into implementation, review, and verification checks for the affected component.

CWE-764: Multiple Locks of a Critical Resource — MITRE CWE

Triage CWE-764 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-764, Multiple Locks of a Critical Resource, 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-764

Apply MITRE's full root-cause mapping guidance when using CWE-764, Multiple Locks of a Critical Resource. 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-764 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-764, Multiple Locks of a Critical Resource. 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-764: Multiple Locks of a Critical Resource?+

CWE-764: Multiple Locks of a Critical Resource is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product locks a critical resource more times than intended, leading to an unexpected state in the system. When a product is operating in a concurrent environment and repeatedly locks a critical resource, the consequences will vary based on the type of lock, the lock's implementation, and the resource being protected. In some situations such as with semaphores, the resources are pooled and extra locking calls will reduce the size of the total available pool, possibly leading to degraded performance or a denial of service. If this can be triggered by an attacker, it will be similar to an unrestricted lock (CWE-412). In the context of a binary lock, it is likely that any duplicate locking attempts will never succeed since the lock is already held and progress may not be possible.

What are the security consequences of Multiple Locks of a Critical Resource?+

If exploited, CWE-764 (Multiple Locks of a Critical Resource) it can compromise Availability and Integrity, leading to outcomes such as DoS: Resource Consumption (CPU), DoS: Crash, Exit, or Restart and Unexpected State.

How do you prevent or mitigate Multiple Locks of a Critical Resource?+

Recommended mitigations for CWE-764 include: When locking and unlocking a resource, try to be sure that all control paths through the code in which the resource is locked one or more times correspond to exactly as many unlocks. If the software acquires a lock and then determines it is not able to perform its intended behavior, be sure to release the lock(s) before waiting for conditions to improve. Reacquire the lock(s) before trying again.

Which programming languages are affected by Multiple Locks of a Critical Resource?+

CWE-764 commonly affects Not Language-Specific. 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-764 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-764: Multiple Locks of a Critical Resource

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