CWE-446 Class Incomplete

UI Discrepancy for Security Feature

This vulnerability occurs when a user interface incorrectly displays a security feature as active or properly configured, misleading users into believing they are protected when they are not.

Definition

What is CWE-446?

This vulnerability occurs when a user interface incorrectly displays a security feature as active or properly configured, misleading users into believing they are protected when they are not.
This flaw creates a dangerous gap between what the user sees and what the system actually does. For example, a user might toggle a setting labeled "Enable end-to-end encryption" and see a visual confirmation, but the underlying software fails to activate the encryption layer. The interface provides a false positive, leaving data exposed during transmission. These discrepancies often stem from poor synchronization between the UI state and the backend security controls. Another common scenario is when a user sets an access control rule to "Deny All," but the system only implements a weaker "Deny Some" policy. This erodes trust and can lead directly to security breaches because users rely on visual feedback that does not match reality.
Real-world impact

Real-world CVEs caused by CWE-446

  • CVE-1999-1446

    UI inconsistency; visited URLs list not cleared when "Clear History" option is selected.

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Secure code example

Secure pseudo

Secure pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist

How to prevent CWE-446

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Detection signals

How to detect CWE-446

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

Plexicus auto-fix

Plexicus auto-detects CWE-446 and opens a fix PR in under 60 seconds.

Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.

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Frequently asked questions

Frequently asked questions

What is CWE-446?

This vulnerability occurs when a user interface incorrectly displays a security feature as active or properly configured, misleading users into believing they are protected when they are not.

How serious is CWE-446?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-446?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-446?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

How does Plexicus detect and fix CWE-446?

Plexicus's SAST engine matches the data-flow signature for CWE-446 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-446?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/446.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-446

CWE-684 Parent

Incorrect Provision of Specified Functionality

This weakness occurs when software behaves differently than its documented specifications, which can mislead users and create security…

CWE-1245 Sibling

Improper Finite State Machines (FSMs) in Hardware Logic

This vulnerability occurs when hardware logic contains flawed Finite State Machines (FSMs). Attackers can exploit these design errors to…

CWE-392 Sibling

Missing Report of Error Condition

This vulnerability occurs when a system fails to properly signal that an error has happened. Instead of returning a clear error code,…

CWE-393 Sibling

Return of Wrong Status Code

This vulnerability occurs when a function returns an inaccurate status code or value that misrepresents the actual outcome of an…

CWE-440 Sibling

Expected Behavior Violation

This weakness occurs when a software component, such as a function, API, or feature, fails to act as documented or intended. The system's…

CWE-451 Sibling

User Interface (UI) Misrepresentation of Critical Information

This vulnerability occurs when a user interface fails to accurately display or highlight crucial information, potentially misleading users…

CWE-912 Sibling

Hidden Functionality

Hidden functionality refers to undocumented features, commands, or code within a product that are not part of its official specification…

CWE-447 Child

Unimplemented or Unsupported Feature in UI

This vulnerability occurs when a user interface displays a security feature as active and functional, but the underlying code that powers…

CWE-448 Child

Obsolete Feature in UI

This vulnerability occurs when a user interface (UI) includes outdated or deprecated features, but fails to alert users about their…

Resources

Further reading

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