CWE-432 Base Draft

Dangerous Signal Handler not Disabled During Sensitive Operations

This vulnerability occurs when a program's signal handler, which shares resources like global variables with other handlers, can be interrupted and re-entered before it finishes its work. The…

Definition

What is CWE-432?

This vulnerability occurs when a program's signal handler, which shares resources like global variables with other handlers, can be interrupted and re-entered before it finishes its work. The program fails to block other signals during this sensitive operation, leaving shared state vulnerable to corruption.
Signal handlers in a program often run with elevated privileges and manage critical data. If a handler is written to share state—like global variables or file descriptors—with other handlers, and the program doesn't temporarily disable (or 'mask') incoming signals, a major risk emerges. An attacker can exploit this by sending a second signal while the first handler is still executing, triggering a different handler that modifies the same shared resources. This uncontrolled interruption corrupts the program's internal state because the first handler's assumptions about that state become invalid. The result is often a crash, data loss, or undefined behavior that an attacker can potentially leverage to gain control of the application or cause a denial of service. To prevent this, developers must design signal handlers to either be re-entrant (stateless) or ensure all related signals are masked for the handler's entire duration.
Real-world impact

Real-world CVEs caused by CWE-432

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-432

  • Implementation Turn off dangerous handlers when performing sensitive operations.
Detection signals

How to detect CWE-432

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-432 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.

Get a demo Try Plexicus free
Frequently asked questions

Frequently asked questions

What is CWE-432?

This vulnerability occurs when a program's signal handler, which shares resources like global variables with other handlers, can be interrupted and re-entered before it finishes its work. The program fails to block other signals during this sensitive operation, leaving shared state vulnerable to corruption.

How serious is CWE-432?

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-432?

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

How can I prevent CWE-432?

Turn off dangerous handlers when performing sensitive operations.

How does Plexicus detect and fix CWE-432?

Plexicus's SAST engine matches the data-flow signature for CWE-432 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-432?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/432.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-432

CWE-364 Parent

Signal Handler Race Condition

A signal handler race condition occurs when a program's signal handling routine is vulnerable to timing issues, allowing its state to be…

CWE-828 Sibling

Signal Handler with Functionality that is not Asynchronous-Safe

This weakness occurs when a program's signal handler contains code that is not asynchronous-safe. This means the handler can be…

CWE-831 Sibling

Signal Handler Function Associated with Multiple Signals

This vulnerability occurs when a single function is registered to handle multiple different operating system signals, creating potential…

Resources

Further reading

Ready when you are

Don't Let Security
Weigh You Down.

Stop choosing between AI velocity and security debt. Plexicus is the only platform that runs Vibe Coding Security and ASPM in parallel — one workflow, every codebase.