What is CWE-416: Use After Free?+
CWE-416: Use After Free is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Is CWE-416 in the CWE Top 25 Most Dangerous Software Weaknesses?+
Yes. CWE-416 ranked #16 in the CWE Top 25 for 2024, associated with 1,151 CVEs that year. The CWE Top 25 highlights the most common and impactful software weaknesses based on real-world vulnerability data.
What are the security consequences of Use After Free?+
If exploited, CWE-416 (Use After Free) it can compromise Integrity, Availability and Confidentiality, leading to outcomes such as Modify Memory, DoS: Crash, Exit, or Restart, Read Memory and Execute Unauthorized Code or Commands.
How do you prevent or mitigate Use After Free?+
Recommended mitigations for CWE-416 include: Choose a language that provides automatic memory management. When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Which programming languages are affected by Use After Free?+
CWE-416 commonly affects C, C++ and Memory-Unsafe. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
What are real-world examples of Use After Free?+
MITRE documents real CVEs mapped to CWE-416, including CVE-2023-38160, CVE-2022-20141, CVE-2022-2621, CVE-2021-0920 and CVE-2020-6819. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
What is the difference between a CWE and a CVE?+
A CWE (Common Weakness Enumeration) like CWE-416 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.