CWE-636: Not Failing Securely ('Failing Open')

What is CWE-636?

CWE-636 is Not Failing Securely ('Failing Open'). The flaw arises when when the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions. The database currently holds 45 vulnerabilities mapped to CWE-636 and none of them are in the CISA Known Exploited Vulnerabilities catalog.

Analyzing data...

OWASP TOP 10:2025 RANK10 — A10:2025 — Mishandling of Exceptional Conditions
Related CVES (365 days)45
AbstractionClass
Likelihood of exploit-

Vulnerabilities mapped to CWE-636

45 vulnerabilities

No data

No vulnerability data in CISA KEV for CWE-636

Official definition

ByMitre CWE

When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.

By entering a less secure state, the product inherits the weaknesses associated with that state, making it easier to compromise. At the least, it causes administrators to have a false sense of security. This weakness typically occurs as a result of wanting to "fail functional" to minimize administration and support costs, instead of "failing safe."

Characteristics

Alternate terms

  • Failing Open

Modes of introduction

  • Architecture and Design
  • Implementation

Common consequences

ImpactScopeExplanation
Bypass Protection MechanismAccess ControlIntended access restrictions can be bypassed, which is often contradictory to what the product's administrator expects.

Risk mitigations

  1. Architecture and DesignSubdivide and allocate resources and components so that a failure in one part does not affect the entire product.

Representative vulnerabilities

Sources (2)

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