The weakness causes crash of software applied for following and removing of unnecessary information from allocated memory after using. Gradually all undeleted data devour leftover memory. Such problems are often provoked by distorted information or suddenly interrupted session.
Usually memory leak is connected with software security. But because of memory shortage attacker can easily perform denial of service attack and gain control over any of other programs.
The weakness is introduced during Architecture and Design, Implementation stages.
Latest vulnerabilities for CWE-401
Description of CWE-401 on Mitre website