CWE•Base•Draft•4 recent CVEs

CWE-390Detection of Error Condition Without Action

The product detects a specific error, but takes no actions to handle the error.

Integrity,Other→Varies by Context,Unexpected State,Alter Execution Logic
An attacker could utilize an ignored error condition to place the system in an unexpected state that could lead to the execution of unintended logic and could cause other unintended behavior.

Implementation
Properly handle each exception. This is the recommended solution. Ensure that all exceptions are handled in such a way that you can be sure of the state of your system at any given moment.
Implementation
If a function returns an error, it is important to either fix the problem and try again, alert the user that an error has happened and let the program continue, or alert the user and close and cleanup the program.
Testing
Subject the product to extensive testing to discover some of the possible instances of where/how errors or return values are not handled. Consider testing techniques such as ad hoc, equivalence partitioning, robustness and fault tolerance, mutation, and fuzzing.