CWE-249 Variant Deprecated

DEPRECATED: Often Misused: Path Manipulation

This entry has been deprecated. Its content was unclear and combined multiple security issues. Most relevant information has been moved to CWE-785.

Definition

What is CWE-249?

This entry has been deprecated. Its content was unclear and combined multiple security issues. Most relevant information has been moved to CWE-785.
This entry was retired primarily due to confusion around the term 'Path Manipulation.' Different security tools and researchers used this same label for completely different problems—from controlling file paths (CWE-73) to buffer management issues. This made it difficult for developers to find consistent guidance, so the entry was split to improve clarity. The second reason for deprecation was that it unintentionally merged two distinct weaknesses. It focused on path-conversion functions that could cause buffer overflows, but also included cases where pathnames were truncated without overflowing buffers—a separate information loss issue. Moving forward, these concepts are addressed in more specific entries to provide better, actionable security advice.
Real-world impact

Real-world CVEs caused by CWE-249

No public CVE references are linked to this CWE in MITRE's catalog yet.

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-249

  • 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-249

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

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Frequently asked questions

Frequently asked questions

What is CWE-249?

This entry has been deprecated. Its content was unclear and combined multiple security issues.

How serious is CWE-249?

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-249?

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

How can I prevent CWE-249?

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-249?

Plexicus's SAST engine matches the data-flow signature for CWE-249 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-249?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/249.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-249

No related weaknesses indexed for this CWE.

Resources

Further reading

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