The product uses an API function, data structure, or other entity in a way that relies on properties that are not always guaranteed to hold for that entity.

What CVEs are caused by CWE-758?

19 recorded CVEs are attributed to CWE-758, including CVE-2026-4705, CVE-2026-4724, CVE-2026-24407.

How is CWE-758 detected?

Fuzzing: Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.

What are the consequences of CWE-758?

Exploiting CWE-758 can lead to: Reduce Maintainability, Unexpected State, Quality Degradation.

Is CWE-758 actively exploited?

19 recorded CVEs are caused by CWE-758; none are currently in CISA's KEV catalog of actively exploited flaws.

CWE-758: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

RadicalNotion.AI

Code examples

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

This code assumes a particular function will always be found at a particular address. It assigns a pointer to that address and calls the function.

Vulnerable example

// Here we can inject code to execute.
int (*pt2Function) (float, char, char)=0x08040000;

The same function may not always be found at the same memory address. This could lead to a crash, or an attacker may alter the memory at the expected address, leading to arbitrary code execution.

The following function returns a stack address.

Vulnerable example

char* getName() {

CWE-758: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to detect it

Fuzzing

Code examples

Illustrative examples

Terminology & mappings

Mapped taxonomies

Frequently asked questions

References

Stay ahead of CWE-758

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to detect it

Fuzzing

Code examples

Illustrative examples

Related weaknesses

Parent

Child

Terminology & mappings

Mapped taxonomies

Frequently asked questions

References

Stay ahead of CWE-758