What CVEs are caused by CWE-662?

15 recorded CVEs are attributed to CWE-662, including CVE-2024-32644, CVE-2024-7409, CVE-2023-20625.

What are the consequences of CWE-662?

Exploiting CWE-662 can lead to: Modify Application Data, Read Application Data, Alter Execution Logic.

Is CWE-662 actively exploited?

15 recorded CVEs are caused by CWE-662; none are currently in CISA's KEV catalog of actively exploited flaws.

Class weakness

Draft

CWE-662: Improper Synchronization

The product utilizes multiple threads, processes, components, or systems to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes.

Last updated May 1, 2026

Recorded CVEs

With this primary weakness

KEVs

In the CISA KEV catalog

Not rated

Likelihood of exploit

Per MITRE

Class

Abstraction

MITRE classification

Overview

Synchronization refers to a variety of behaviors and mechanisms that allow two or more independently-operating processes or threads to ensure that they operate on shared resources in predictable ways that do not interfere with each other. Some shared resource operations cannot be executed atomically; that is, multiple steps must be guaranteed to execute sequentially, without any interference by other processes. Synchronization mechanisms vary widely, but they may include locking, mutexes, and semaphores. When a multi-step operation on a shared resource cannot be guaranteed to execute independent of interference, then the resulting behavior can be unpredictable. Improper synchronization could lead to data or memory corruption, denial of service, etc.

Real-world CVEs

15 recorded CVEs are caused by CWE-662 (Improper Synchronization). The highest-severity and most recent are shown first. 1 new CWE-662 CVE has been recorded so far in 2026 (2 in 2025).

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Common consequences

What can happen when CWE-662 is exploited.

Modify Application Data, Read Application Data, Alter Execution Logic

Affects: Integrity, Confidentiality, Other

How it happens

When it is introduced

Typically introduced during these phases of the software lifecycle.

Architecture and Design

Implementation

How to prevent it

Practical mitigations for CWE-662, grouped by where in the lifecycle they apply.

Implementation

Use industry standard APIs to synchronize your code.

How to detect it

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Code examples

Illustrative examples from MITRE showing how the weakness appears in code.

The following function attempts to acquire a lock in order to perform operations on a shared resource.

Vulnerable example

void f(pthread_mutex_t *mutex) {

Safe example

int f(pthread_mutex_t *mutex) {

The following code intends to fork a process, then have both the parent and child processes print a single line.

Vulnerable example

static void print (char * string) {

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

CVE-2021-1782
CISA KEV
— Chain: improper locking (CWE-667) leads to race condition (CWE-362), as exploited in the wild per CISA KEV.
CVE-2009-0935 — Attacker provides invalid address to a memory-reading function, causing a mutex to be unlocked twice

Terminology & mappings

Mapped taxonomies

CERT C Secure Coding: Mask signals handled by noninterruptible signal handlers (SIG00-C)
CERT C Secure Coding: Do not access shared objects in signal handlers (SIG31-C) — CWE More Abstract fit
CLASP: State synchronization error
The CERT Oracle Secure Coding Standard for Java (2011): Do not assume that a group of calls to independently atomic methods is atomic (VNA03-J)
Software Fault Patterns: Missing Lock (SFP19)

Attack patterns

CAPEC attack patterns that exploit this weakness.

Frequently asked questions

Common questions about CWE-662.

What is CWE-662?: The product utilizes multiple threads, processes, components, or systems to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes.
What CVEs are caused by CWE-662?: 15 recorded CVEs are attributed to CWE-662, including CVE-2024-32644, CVE-2024-7409, CVE-2023-20625.
How do you prevent CWE-662?: Use industry standard APIs to synchronize your code.
How is CWE-662 detected?: Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
What are the consequences of CWE-662?: Exploiting CWE-662 can lead to: Modify Application Data, Read Application Data, Alter Execution Logic.
Is CWE-662 actively exploited?: 15 recorded CVEs are caused by CWE-662; none are currently in CISA's KEV catalog of actively exploited flaws.

References

Weakness data is sourced from the MITRE CWE catalog (v4.20). CVE associations are aggregated and kept current by RadicalNotion.AI.

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