Mishandling of Exceptional Conditions
A new category containing 24 CWEs focusing on improper error handling, logical errors, failing open, and other scenarios stemming from abnormal conditions that systems may encounter.
Overview
New category for 2025. Focuses on how applications handle errors, edge cases, and exceptional conditions. Improper handling can lead to information disclosure, denial of service, or security control bypass.
How Attackers Exploit This
Understanding attack patterns helps you build better defenses. These are the techniques security teams watch for.
Fail-open bypass
Security controls fail open when exceptions occur, allowing unauthorized access when the system encounters unexpected conditions.
Error-based information disclosure
Detailed error messages reveal internal system information, database schemas, or file paths to attackers.
Resource exhaustion
Triggering exceptional conditions repeatedly causes resource exhaustion or denial of service.
How to Prevent
- Implement consistent error handling across the application
- Design systems to fail securely (fail closed, not fail open)
- Handle all exception types explicitly, never use catch-all silently
- Return generic error messages to users, log detailed errors internally
- Test error handling paths with invalid, unexpected, and malicious input
- Implement timeouts and circuit breakers for external dependencies
- Validate assumptions about inputs and system state
CWEs with Shoulder Detection (6)
These CWEs have Shoulder detection rules. Click to see specific vulnerabilities and fixes.
Other Mapped CWEs (18)
These CWEs are mapped to this category. Use MITRE references for guidance.