CWEweakness
CWE-636 Not Failing Securely
- Alternate terms
- Failing Open
- Abstraction
- Class
- Structure
- Simple
- Status
- Draft
- Languages
- Not Language-Specific
- CWE version
- 5.0
Description
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.
Common consequences
• Other: Varies by Context — 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.
• Access Control: Bypass Protection Mechanism — Intended access restrictions can be bypassed, which is often contradictory to what the product's administrator expects.
Potential mitigations
• [Architecture and Design] Subdivide and allocate resources and components so that a failure in one part does not affect the entire product.
Observed examples
• CVE-2007-5277: The failure of connection attempts in a web browser resets DNS pin restrictions. An attacker can then bypass the same origin policy by rebinding a domain name to a different IP address. This was an attempt to "fail functional."
• CVE-2006-4407: Incorrect prioritization leads to the selection of a weaker cipher. Although it is not known whether this issue occurred in implementation or design, it is feasible that a poorly designed algorithm could be a factor.
Related
Observed example · CVE (2)
- CVE-2007-5277 Microsoft Internet Explorer 6 drops DNS pins based on failed connections to irrelevant TCP ports, which makes it easier for remote… vulnerability
- CVE-2006-4407 The Security Framework in Apple Mac OS X 10.3.x up to 10.3.9 does not properly prioritize encryption ciphers when negotiating the strongest… vulnerability
Child of · CWE (2)
Peer of · CWE (1)
- CWE-280 Improper Handling of Insufficient Permissions or Privileges weakness
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- CVE-2026-46482 ### Impact The registration component does not validate the text-based _Security Question_ CAPTCHA correctly, allowing attackers to bypass… vulnerability
Referenced by CWE · child of (1)
- CWE-455 Non-exit on Failed Initialization weakness
Referenced by OWASP · mapped cwe (1)
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