0xc0000005 is a Windows error code that maps to STATUS_ACCESS_VIOLATION. It usually means a process tried to read, write, or execute memory it was not allowed to access. In practice, this often shows up as an application crash, a service failure, or a sudden termination of a security tool.
In cyber security, this code matters because it can point to many different causes: a software bug, memory corruption, a bad update, or an exploit attempt. Analysts use it to triage crashes in endpoint protection, browsers, and other high-value software. When a defender product crashes with 0xc0000005, teams check logs, dumps, and update history to separate a patch regression from malicious tampering or exploit-driven behavior. The code is a symptom, not proof of compromise.