The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.

What CVEs are caused by CWE-772?

71 recorded CVEs are attributed to CWE-772, including CVE-2024-20481, CVE-2026-39830, CVE-2020-14339. 1 are listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.

How do you prevent CWE-772?

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

How is CWE-772 detected?

Automated Static Analysis: 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.)

What are the consequences of CWE-772?

Exploiting CWE-772 can lead to: DoS: Resource Consumption (Other), DoS: Resource Consumption (Memory), DoS: Resource Consumption (CPU).

Is CWE-772 actively exploited?

Yes. 1 CWE-772 vulnerabilities are in CISA's KEV catalog of actively exploited flaws, out of 71 recorded CVEs.

CWE-772: Missing Release of Resource after Effective Lifetime

Code examples

Illustrative examples from MITRE showing how the weakness appears in code.

The following method never closes the new file handle. Given enough time, the Finalize() method for BufferReader should eventually call Close(), but there is no guarantee as to how long this action will take. In fact, there is no guarantee that Finalize() will ever be invoked. In a busy environment, the Operating System could use up all of the available file handles before the Close() function is called.

Vulnerable example

java

private void processFile(string fName)

Safe example

java

private void processFile(string fName)

The good code example simply adds an explicit call to the Close() function when the system is done using the file. Within a simple example such as this the problem is easy to see and fix. In a real system, the problem may be considerably more obscure.

The following code attempts to open a new connection to a database, process the results returned by the database, and close the allocated SqlConnection object.

Vulnerable example

csharp

SqlConnection conn = new SqlConnection(connString);

The problem with the above code is that if an exception occurs while executing the SQL or processing the results, the SqlConnection object is not closed. If this happens often enough, the database will run out of available cursors and not be able to execute any more SQL queries.

This code attempts to open a connection to a database and catches any exceptions that may occur.

Vulnerable example

java

try {

If an exception occurs after establishing the database connection and before the same connection closes, the pool of database connections may become exhausted. If the number of available connections is exceeded, other users cannot access this resource, effectively denying access to the application.

Under normal conditions the following C# code executes a database query, processes the results returned by the database, and closes the allocated SqlConnection object. But if an exception occurs while executing the SQL or processing the results, the SqlConnection object is not closed. If this happens often enough, the database will run out of available cursors and not be able to execute any more SQL queries.

The following C function does not close the file handle it opens if an error occurs. If the process is long-lived, the process can run out of file handles.

Vulnerable example

int decodeFile(char* fName) {

CWE-772: Missing Release of Resource after Effective Lifetime

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

Applies to

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Terminology & mappings

Mapped taxonomies

Attack patterns

Frequently asked questions

References

Stay ahead of CWE-772

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

Applies to

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Related weaknesses

Parent

Child

Related

Terminology & mappings

Mapped taxonomies

Attack patterns

Frequently asked questions

References

Stay ahead of CWE-772