CWE-459 Base Draft

Incomplete Cleanup

This vulnerability occurs when an application fails to properly remove temporary files, data structures, or system resources after they are no longer needed.

Definition

What is CWE-459?

This vulnerability occurs when an application fails to properly remove temporary files, data structures, or system resources after they are no longer needed.
Incomplete cleanup happens when developers focus on the primary function of their code but neglect the final 'housekeeping' steps. This often involves forgetting to close file handles, database connections, or network sockets, or leaving temporary files in shared directories. These leftover resources can accumulate over time, leading to performance degradation, data leaks, or denial of service as system limits are reached. From a security perspective, uncleaned temporary files can expose sensitive data to other users or processes on the system. In multi-user environments, this can allow unauthorized access to session tokens, configuration secrets, or user data. The risk is particularly high when predictable filenames are used, as attackers can easily locate and exploit these residual artifacts.
Real-world impact

Real-world CVEs caused by CWE-459

  • CVE-2000-0552

    World-readable temporary file not deleted after use.

  • CVE-2005-2293

    Temporary file not deleted after use, leaking database usernames and passwords.

  • CVE-2002-0788

    Interaction error creates a temporary file that can not be deleted due to strong permissions.

  • CVE-2002-2066

    Alternate data streams for NTFS files are not cleared when files are wiped (alternate channel / infoleak).

  • CVE-2002-2067

    Alternate data streams for NTFS files are not cleared when files are wiped (alternate channel / infoleak).

  • CVE-2002-2068

    Alternate data streams for NTFS files are not cleared when files are wiped (alternate channel / infoleak).

  • CVE-2002-2069

    Alternate data streams for NTFS files are not cleared when files are wiped (alternate channel / infoleak).

  • CVE-2002-2070

    Alternate data streams for NTFS files are not cleared when files are wiped (alternate channel / infoleak).

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 Java

Stream resources in a Java application should be released in a finally block, otherwise an exception thrown before the call to close() would result in an unreleased I/O resource. In the example below, the close() method is called in the try block (incorrect).

Vulnerable Java 
try {
  	InputStream is = new FileInputStream(path);
  	byte b[] = new byte[is.available()];
  	is.read(b);
  	is.close();
  } catch (Throwable t) {
  	log.error("Something bad happened: " + t.getMessage());
  }
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-459

  • Architecture and Design / Implementation Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
Detection signals

How to detect CWE-459

Automated Static Analysis High

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Plexicus auto-fix

Plexicus auto-detects CWE-459 and opens a fix PR in under 60 seconds.

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Frequently asked questions

Frequently asked questions

What is CWE-459?

This vulnerability occurs when an application fails to properly remove temporary files, data structures, or system resources after they are no longer needed.

How serious is CWE-459?

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-459?

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

How can I prevent CWE-459?

Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.

How does Plexicus detect and fix CWE-459?

Plexicus's SAST engine matches the data-flow signature for CWE-459 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-459?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/459.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-459

CWE-404 Parent

Improper Resource Shutdown or Release

This vulnerability occurs when a program fails to properly close or release a system resource—like a file handle, database connection, or…

CWE-1266 Sibling

Improper Scrubbing of Sensitive Data from Decommissioned Device

This vulnerability occurs when a system lacks a reliable method for administrators to permanently erase sensitive information before…

CWE-299 Sibling

Improper Check for Certificate Revocation

This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially…

CWE-401 Sibling

Missing Release of Memory after Effective Lifetime

This vulnerability occurs when a program allocates memory but fails to properly release it after it's no longer needed, causing a gradual…

CWE-761 Sibling

Free of Pointer not at Start of Buffer

This vulnerability occurs when a program incorrectly frees a memory pointer that no longer points to the beginning of the allocated heap…

CWE-762 Sibling

Mismatched Memory Management Routines

This vulnerability occurs when a program uses incompatible functions to allocate and free memory. For example, freeing memory with a…

CWE-763 Sibling

Release of Invalid Pointer or Reference

This vulnerability occurs when a program tries to free a memory resource back to the system but uses an incorrect deallocation method or…

CWE-772 Sibling

Missing Release of Resource after Effective Lifetime

This vulnerability occurs when a program fails to properly release a system resource—like memory, file handles, or network sockets—after…

CWE-775 Sibling

Missing Release of File Descriptor or Handle after Effective Lifetime

This vulnerability occurs when a program fails to properly close file descriptors or handles after they are no longer needed, leaving…

Resources

Further reading

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