Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.
The UI Performs the Wrong Action
This vulnerability occurs when a user interface (UI) element or command performs a different, unintended action than what the user requested, potentially leading to security bypass, data corruption,…
What is CWE-449?
Real-world CVEs caused by CWE-449
-
Network firewall accidentally implements one command line option as if it were another, possibly leading to behavioral infoleak.
-
Command line option correctly suppresses a user prompt but does not properly disable a feature, although when the product prompts the user, the feature is properly disabled.
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Product does not "time out" according to user specification, leaving sensitive data available after it has expired.
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable pseudo
MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} How to prevent CWE-449
- Testing Perform extensive functionality testing of the UI. The UI should behave as specified.
How to detect CWE-449
Run dynamic application security testing against the live endpoint.
Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.
Code review: flag any new code that handles input from this surface without using the validated framework helpers.
Plexicus auto-detects CWE-449 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.
Frequently asked questions
What is CWE-449?
This vulnerability occurs when a user interface (UI) element or command performs a different, unintended action than what the user requested, potentially leading to security bypass, data corruption, or unexpected system behavior.
How serious is CWE-449?
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-449?
MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.
How can I prevent CWE-449?
Perform extensive functionality testing of the UI. The UI should behave as specified.
How does Plexicus detect and fix CWE-449?
Plexicus's SAST engine matches the data-flow signature for CWE-449 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-449?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/449.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Weaknesses related to CWE-449
UI Discrepancy for Security Feature
This vulnerability occurs when a user interface incorrectly displays a security feature as active or properly configured, misleading users…
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…
Obsolete Feature in UI
This vulnerability occurs when a user interface (UI) includes outdated or deprecated features, but fails to alert users about their…
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