CWE-395: Use of NullPointerException Catch to Detect NULL Pointer Dereference

BaseDraft

Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer.

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Extended Description

Programmers typically catch NullPointerException under three circumstances: The program contains a null pointer dereference. Catching the resulting exception was easier than fixing the underlying problem. The program explicitly throws a NullPointerException to signal an error condition. The code is part of a test harness that supplies unexpected input to the classes under test. Of these three circumstances, only the last is acceptable.

Technical Details

Structure
Simple
Vulnerability Mapping
ALLOWED

Applicable To

Languages
Java
Platforms

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-395 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-395, Use of NullPointerException Catch to Detect NULL Pointer Dereference, 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 NullPointerException Catch to Detect NULL Pointer Dereference during Architecture and Design

MITRE associates mitigation with Architecture and Design, and Implementation; documented detection approaches include Automated Static Analysis - Binary or Bytecode, Dynamic Analysis with Manual Results Interpretation, Manual Static Analysis - Source Code, and Automated Static Analysis - Source Code; recorded impacts include DoS: Resource Consumption (CPU). Use these source-defined anchors to turn CWE-395 into implementation, review, and verification checks for the affected component.

CWE-395: Use of NullPointerException Catch to Detect NULL Pointer Dereference — MITRE CWE

Triage CWE-395 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-395, Use of NullPointerException Catch to Detect NULL Pointer Dereference, 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-395

Apply MITRE's full root-cause mapping guidance when using CWE-395, Use of NullPointerException Catch to Detect NULL Pointer Dereference. 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-395 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-395, Use of NullPointerException Catch to Detect NULL Pointer Dereference. 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-395: Use of NullPointerException Catch to Detect NULL Pointer Dereference?+

CWE-395: Use of NullPointerException Catch to Detect NULL Pointer Dereference is a Common Weakness Enumeration (CWE) entry maintained by MITRE. Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer. Programmers typically catch NullPointerException under three circumstances: The program contains a null pointer dereference. Catching the resulting exception was easier than fixing the underlying problem. The program explicitly throws a NullPointerException to signal an error condition. The code is part of a test harness that supplies unexpected input to the classes under test. Of these three circumstances, only the last is acceptable.

What are the security consequences of Use of NullPointerException Catch to Detect NULL Pointer Dereference?+

If exploited, CWE-395 (Use of NullPointerException Catch to Detect NULL Pointer Dereference) it can compromise Availability, leading to outcomes such as DoS: Resource Consumption (CPU).

How do you prevent or mitigate Use of NullPointerException Catch to Detect NULL Pointer Dereference?+

Recommended mitigations for CWE-395 include: Do not extensively rely on catching exceptions (especially for validating user input) to handle errors. Handling exceptions can decrease the performance of an application.

How is Use of NullPointerException Catch to Detect NULL Pointer Dereference detected?+

CWE-395 can be detected using Automated Static Analysis - Binary or Bytecode, Dynamic Analysis with Manual Results Interpretation, Manual Static Analysis - Source Code, Automated Static Analysis - Source Code and Architecture or Design Review. Combining automated tooling with manual review typically yields the best coverage.

Which programming languages are affected by Use of NullPointerException Catch to Detect NULL Pointer Dereference?+

CWE-395 commonly affects Java. 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-395 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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