CWE-568 Variant Draft

finalize() Method Without super.finalize()

This vulnerability occurs when a Java class overrides the finalize() method but fails to call super.finalize() within it.

Definition

What is CWE-568?

This vulnerability occurs when a Java class overrides the finalize() method but fails to call super.finalize() within it.
In Java, the finalize() method is called by the garbage collector before an object is destroyed. If you override this method in a subclass and omit the call to super.finalize(), you break the cleanup chain. This prevents the parent class from performing its own essential cleanup operations, which can lead to resource leaks like unclosed file handles or database connections. To prevent this, always include super.finalize() as the final action in your overridden finalize method. While modern Java development often recommends using cleaner alternatives like try-with-resources or AutoCloseable for resource management, maintaining the super.finalize() call remains a critical defensive practice in legacy code or when overriding finalize is unavoidable.
Real-world impact

Real-world CVEs caused by CWE-568

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 Java

The following method omits the call to super.finalize().

Vulnerable Java 
protected void finalize() {
  	discardNative();
  }
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-568

  • Implementation Call the super.finalize() method.
  • Testing Use static analysis tools to spot such issues in your code.
Detection signals

How to detect CWE-568

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-568 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-568?

This vulnerability occurs when a Java class overrides the finalize() method but fails to call super.finalize() within it.

How serious is CWE-568?

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-568?

MITRE lists the following affected platforms: Java.

How can I prevent CWE-568?

Call the super.finalize() method. Use static analysis tools to spot such issues in your code.

How does Plexicus detect and fix CWE-568?

Plexicus's SAST engine matches the data-flow signature for CWE-568 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-568?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/568.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-568

CWE-459 Parent

Incomplete Cleanup

This vulnerability occurs when an application fails to properly remove temporary files, data structures, or system resources after they…

CWE-226 Sibling

Sensitive Information in Resource Not Removed Before Reuse

This vulnerability occurs when a system releases a resource like memory or a file for reuse but fails to erase the sensitive data it…

CWE-460 Sibling

Improper Cleanup on Thrown Exception

This vulnerability occurs when a program fails to properly restore its state or release resources after an exception is thrown, leaving…

Resources

Further reading

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