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.
View on MITREThis can lead to resultant weaknesses when the required properties change, such as when the product is ported to a different platform or if an interaction error (CWE-435) occurs.
No mitigation information available for this CWE.
No detection method information available for this CWE.
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.
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.
int (*pt2Function) (float, char, char)=0x08040000;int result2 = (*pt2Function) (12, 'a', 'b'); // Here we can inject code to execute.The following function returns a stack address.
char* getName() {char name[STR_MAX];fillInName(name);return name;}Change in C compiler behavior causes resultant buffer overflows in programs that depend on behaviors that were undefined in the C standard.
View DetailsAdditional facts reviewed against primary or authoritative security sources.
Documented detection approaches include Fuzzing; recorded impacts include Reduce Maintainability, Unexpected State, and Quality Degradation; observed examples include CVE-2006-1902. Use these source-defined anchors to turn CWE-758 into implementation, review, and verification checks for the affected component.
CWE-758: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior — MITRE CWEUse NIST SSDF practices to make prevention of CWE-758, Reliance on Undefined, Unspecified, or Implementation-Defined Behavior, an explicit development outcome. Translate the CWE definition into security requirements and design constraints, choose safer implementation patterns and toolchain checks, and define acceptance evidence before release. Feed every confirmed occurrence back into the requirements, design review, and coding rules so the same root cause is removed across the product rather than patched in one location.
NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and TechnologyUse CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-758, Reliance on Undefined, Unspecified, or Implementation-Defined Behavior, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.
Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security AgencyApply MITRE's full root-cause mapping guidance when using CWE-758, Reliance on Undefined, Unspecified, or Implementation-Defined Behavior. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.
CVE to CWE Root Cause Mapping Guidance — MITRE CWEApply MITRE's root-cause mapping quick tips to CWE-758, Reliance on Undefined, Unspecified, or Implementation-Defined Behavior. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.
CVE to CWE Root Cause Mapping Quick Tips — MITRE CWECWE-758: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior is a Common Weakness Enumeration (CWE) entry maintained by MITRE. 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. This can lead to resultant weaknesses when the required properties change, such as when the product is ported to a different platform or if an interaction error (CWE-435) occurs.
If exploited, CWE-758 (Reliance on Undefined, Unspecified, or Implementation-Defined Behavior) it can compromise Other, leading to outcomes such as Reduce Maintainability, Unexpected State and Quality Degradation.
CWE-758 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
MITRE documents real CVEs mapped to CWE-758, including CVE-2006-1902. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
A CWE (Common Weakness Enumeration) like CWE-758 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.