CWE-675 Class Draft

Multiple Operations on Resource in Single-Operation Context

This vulnerability occurs when a software component performs the same action on a resource multiple times, even though the action is designed to be executed only once. This redundant execution can…

Definition

What is CWE-675?

This vulnerability occurs when a software component performs the same action on a resource multiple times, even though the action is designed to be executed only once. This redundant execution can lead to unintended side effects, data corruption, or resource exhaustion.
Think of this like accidentally hitting 'send' on an email twice. The core issue is that a function or method lacks a proper guard to prevent re-execution on the same target. This often happens in event handlers that don't debounce user clicks, in loops with flawed termination conditions, or when cleanup and initialization routines incorrectly overlap. The duplicate operations waste system resources and can put the application or data into an inconsistent, unpredictable state. For developers, the fix involves implementing idempotence—ensuring an operation produces the same result whether it's run once or multiple times. This can be achieved by using flags to track completion, employing atomic operations, or designing APIs that safely handle repeated calls. Thorough testing with edge cases, especially around user interactions and error recovery paths, is crucial to catch this subtle but impactful flaw.
Real-world impact

Real-world CVEs caused by CWE-675

  • CVE-2009-0935

    Attacker provides invalid address to a memory-reading function, causing a mutex to be unlocked twice

  • CVE-2019-13351

    file descriptor double close can cause the wrong file to be associated with a file descriptor.

  • CVE-2004-1939

    XSS protection mechanism attempts to remove "/" that could be used to close tags, but it can be bypassed using double encoded slashes (%252F)

How attackers exploit it

Step-by-step attacker path

  1. 1

    The following code shows a simple example of a double free vulnerability.

  2. 2

    Double free vulnerabilities have two common (and sometimes overlapping) causes:

  3. 3

    - Error conditions and other exceptional circumstances - Confusion over which part of the program is responsible for freeing the memory

  4. 4

    Although some double free vulnerabilities are not much more complicated than this example, most are spread out across hundreds of lines of code or even different files. Programmers seem particularly susceptible to freeing global variables more than once.

  5. 5

    This code binds a server socket to port 21, allowing the server to listen for traffic on that port.

Vulnerable code example

Vulnerable C

The following code shows a simple example of a double free vulnerability.

Vulnerable C 
char* ptr = (char*)malloc (SIZE);
  ...
  if (abrt) {
  	free(ptr);
  }
  ...
  free(ptr);
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-675

  • 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-675

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-675 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-675?

This vulnerability occurs when a software component performs the same action on a resource multiple times, even though the action is designed to be executed only once. This redundant execution can lead to unintended side effects, data corruption, or resource exhaustion.

How serious is CWE-675?

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-675?

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

How can I prevent CWE-675?

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-675?

Plexicus's SAST engine matches the data-flow signature for CWE-675 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-675?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/675.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-675

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CWE-325 Sibling

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Resources

Further reading

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