CWE-477: Use of Obsolete Function

BaseDraft

The code uses deprecated or obsolete functions, which suggests that the code has not been actively reviewed or maintained.

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Extended Description

As programming languages evolve, functions occasionally become obsolete due to: Advances in the language Improved understanding of how operations should be performed effectively and securely Changes in the conventions that govern certain operations Functions that are removed are usually replaced by newer counterparts that perform the same task in some different and hopefully improved way.

Technical Details

Structure
Simple
Vulnerability Mapping
ALLOWED

Applicable To

Languages
Not Language-Specific
Platforms

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-477 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-477, Use of Obsolete Function, 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 Obsolete Function during Implementation

MITRE associates mitigation with Implementation, and Requirements; documented detection approaches include Automated Static Analysis - Binary or Bytecode, Manual Static Analysis - Binary or Bytecode, Dynamic Analysis with Manual Results Interpretation, and Manual Static Analysis - Source Code; recorded impacts include Quality Degradation. Use these source-defined anchors to turn CWE-477 into implementation, review, and verification checks for the affected component.

CWE-477: Use of Obsolete Function — MITRE CWE

Triage CWE-477 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-477, Use of Obsolete Function, 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-477

Apply MITRE's full root-cause mapping guidance when using CWE-477, Use of Obsolete Function. 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-477 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-477, Use of Obsolete Function. 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-477: Use of Obsolete Function?+

CWE-477: Use of Obsolete Function is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The code uses deprecated or obsolete functions, which suggests that the code has not been actively reviewed or maintained. As programming languages evolve, functions occasionally become obsolete due to: Advances in the language Improved understanding of how operations should be performed effectively and securely Changes in the conventions that govern certain operations Functions that are removed are usually replaced by newer counterparts that perform the same task in some different and hopefully improved way.

What are the security consequences of Use of Obsolete Function?+

If exploited, CWE-477 (Use of Obsolete Function) it can compromise Other, leading to outcomes such as Quality Degradation.

How do you prevent or mitigate Use of Obsolete Function?+

Recommended mitigations for CWE-477 include: Refer to the documentation for the obsolete function in order to determine why it is deprecated or obsolete and to learn about alternative ways to achieve the same functionality. Consider seriously the security implications of using an obsolete function. Consider using alternate functions.

How is Use of Obsolete Function detected?+

CWE-477 can be detected using Automated Static Analysis - Binary or Bytecode, Manual Static Analysis - Binary or Bytecode, Dynamic Analysis with Manual Results Interpretation, Manual Static Analysis - Source Code, Automated Static Analysis - Source Code and Automated Static Analysis. Combining automated tooling with manual review typically yields the best coverage.

Which programming languages are affected by Use of Obsolete Function?+

CWE-477 commonly affects 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-477 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.

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