Base weakness
Incomplete
CWE-821: Incorrect Synchronization
The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource.
Last updated
11
Recorded CVEs
With this primary weakness
0
KEVs
In the CISA KEV catalog
Not rated
Likelihood of exploit
Per MITRE
Base
Abstraction
MITRE classification
Overview
If access to a shared resource is not correctly synchronized, then the resource may not be in a state that is expected by the product. This might lead to unexpected or insecure behaviors, especially if an attacker can influence the shared resource.
Real-world CVEs
11 recorded CVEs are caused by CWE-821 (Incorrect Synchronization). The highest-severity and most recent are shown first. 1 new CWE-821 CVE has been recorded so far in 2026 (3 in 2025).