CyberSecBulletin

Use After Free

CWE-416

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

We track 4,465 vulnerabilities of this type. 100% are rated high or critical, and the average CVSS score is 8.3. 109 have been exploited in real attacks.

How this weakness is prevented

  • Architecture and Design: Choose a language that provides automatic memory management.
  • Implementation: 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.

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