CWE-119 is a weakness class for memory safety bugs where software reads from or writes to memory outside the intended bounds of a buffer. In practice, it includes overflows, out-of-bounds access, and related mistakes in C and C++ code, where the program does not automatically enforce safe memory limits.
This matters because out-of-bounds memory operations can crash services, corrupt data, or sometimes enable code execution. Attackers often look for these flaws in network-facing components such as parsers, gateways, and authentication appliances, since a single malformed request may be enough to trigger failure. Defenders reduce risk with secure coding, bounds checks, safer libraries, compiler hardening, fuzz testing, and rapid patching. When CWE-119 appears in an access-control or identity system, the impact can be especially serious because a memory bug in the front door can become a denial of service for the whole environment.