The product does not initialize a critical resource.

What CVEs are caused by CWE-909?

14 recorded CVEs are attributed to CWE-909, including CVE-2026-40687, CVE-2020-12523, CVE-2025-8117.

How do you prevent CWE-909?

Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all specified steps.

How is CWE-909 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-909?

Exploiting CWE-909 can lead to: Read Memory, Read Application Data, DoS: Crash, Exit, or Restart.

Is CWE-909 actively exploited?

14 recorded CVEs are caused by CWE-909; none are currently in CISA's KEV catalog of actively exploited flaws.

CWE-909: Missing Initialization of Resource

RadicalNotion.AI

Code examples

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

Here, a boolean initiailized field is consulted to ensure that initialization tasks are only completed once. However, the field is mistakenly set to true during static initialization, so the initialization code is never reached.

Vulnerable example

java

private boolean initialized = true;

The following code intends to limit certain operations to the administrator only.

Vulnerable example

perl

# do stuff
$username = GetCurrentUser();

If the application is unable to extract the state information - say, due to a database timeout - then the $uid variable will not be explicitly set by the programmer. This will cause $uid to be regarded as equivalent to "0" in the conditional, allowing the original user to perform administrator actions. Even if the attacker cannot directly influence the state data, unexpected errors could cause incorrect privileges to be assigned to a user just by accident.

The following code intends to concatenate a string to a variable and print the string.

Vulnerable example

char str[20];

This example will leave test_string in an unknown condition when i is the same value as err_val, because test_string is not initialized (CWE-456). Depending on where this code segment appears (e.g. within a function body), test_string might be random if it is stored on the heap or stack. If the variable is declared in static memory, it might be zero or NULL. Compiler optimization might contribute to the unpredictability of this address.

Vulnerable example

test_string = "Hello World!";

Safe example

test_string = "Hello World!";

CWE-909: Missing Initialization of Resource

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Frequently asked questions

References

Stay ahead of CWE-909

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Related weaknesses

Parent

Child

Can precede

Frequently asked questions

References

Stay ahead of CWE-909