CWE-474: Use of Function with Inconsistent Implementations

Extended Description

The use of inconsistent implementations can cause changes in behavior when the code is ported or built under a different environment than the programmer expects, which can lead to security problems in some cases. The implementation of many functions varies by platform, and at times, even by different versions of the same platform. Implementation differences can include: Slight differences in the way parameters are interpreted leading to inconsistent results. Some implementations of the function carry significant security risks. The function might not be defined on all platforms. The function might change which return codes it can provide, or change the meaning of its return codes.

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-474 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-474, Use of Function with Inconsistent Implementations, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Use of Function with Inconsistent Implementations during Architecture and Design

MITRE associates mitigation with Architecture and Design, and Requirements; documented detection approaches include Automated Static Analysis; recorded impacts include Quality Degradation, and Varies by Context. Use these source-defined anchors to turn CWE-474 into implementation, review, and verification checks for the affected component.

CWE-474: Use of Function with Inconsistent Implementations — MITRE CWE

Triage CWE-474 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-474, Use of Function with Inconsistent Implementations, 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 Agency

Apply precise root-cause mapping to CWE-474

Apply MITRE's full root-cause mapping guidance when using CWE-474, Use of Function with Inconsistent Implementations. 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 CWE

Validate CWE-474 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-474, Use of Function with Inconsistent Implementations. 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 CWE

Frequently Asked Questions

What is CWE-474: Use of Function with Inconsistent Implementations?+

CWE-474: Use of Function with Inconsistent Implementations is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The code uses a function that has inconsistent implementations across operating systems and versions. The use of inconsistent implementations can cause changes in behavior when the code is ported or built under a different environment than the programmer expects, which can lead to security problems in some cases. The implementation of many functions varies by platform, and at times, even by different versions of the same platform. Implementation differences can include: Slight differences in the way parameters are interpreted leading to inconsistent results. Some implementations of the function carry significant security risks. The function might not be defined on all platforms. The function might change which return codes it can provide, or change the meaning of its return codes.

What are the security consequences of Use of Function with Inconsistent Implementations?+

If exploited, CWE-474 (Use of Function with Inconsistent Implementations) it can compromise Other, leading to outcomes such as Quality Degradation and Varies by Context.

How do you prevent or mitigate Use of Function with Inconsistent Implementations?+

Recommended mitigations for CWE-474 include: Do not accept inconsistent behavior from the API specifications when the deviant behavior increase the risk level.

Which programming languages are affected by Use of Function with Inconsistent Implementations?+

CWE-474 commonly affects C, PHP and Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-474 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.

CWE-474: Use of Function with Inconsistent Implementations

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