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Home > CWE List > CWE-395: Use of NullPointerException Catch to Detect NULL Pointer Dereference (4.18)
ID
CWE Glossary Definition

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

Weakness ID: 395
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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Description
Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer.
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.

Common Consequences
Section HelpThis table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Impact Details

DoS: Resource Consumption (CPU)

Scope: Availability

Potential Mitigations
Phase(s) Mitigation

Architecture and Design; Implementation
Do not extensively rely on catching exceptions (especially for validating user input) to handle errors. Handling exceptions can decrease the performance of an application.
Relationships
Section Help This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
Relevant to the view "Research Concepts" (View-1000)
Nature Type ID Name
ChildOf Class Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. 705 Incorrect Control Flow Scoping
ChildOf Class Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. 755 Improper Handling of Exceptional Conditions
Relevant to the view "Software Development" (View-699)
Nature Type ID Name
MemberOf Category Category - a CWE entry that contains a set of other entries that share a common characteristic. 389 Error Conditions, Return Values, Status Codes
Modes Of Introduction
Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase Note
Implementation
Applicable Platforms
Section HelpThis listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.
Languages

Java (Undetermined Prevalence)

Demonstrative Examples

Example 1


The following code mistakenly catches a NullPointerException.

(bad code)
Example Language: Java
try {
mysteryMethod();
} catch (NullPointerException npe) {
}


Detection Methods
Method Details

Automated Static Analysis - Binary or Bytecode

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:
  • Bytecode Weakness Analysis - including disassembler + source code weakness analysis
  • Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:
  • Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:
  • Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:
  • Source code Weakness Analyzer
  • Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:
  • Formal Methods / Correct-By-Construction
Cost effective for partial coverage:
  • Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High
Memberships
Section HelpThis MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 388 7PK - Errors
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 851 The CERT Oracle Secure Coding Standard for Java (2011) Chapter 8 - Exceptional Behavior (ERR)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 962 SFP Secondary Cluster: Unchecked Status Condition
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1410 Comprehensive Categorization: Insufficient Control Flow Management
Vulnerability Mapping Notes
Usage ALLOWED
(this CWE ID may be used to map to real-world vulnerabilities)
Reason Acceptable-Use

Rationale

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
7 Pernicious Kingdoms Catching NullPointerException
The CERT Oracle Secure Coding Standard for Java (2011) ERR08-J Do not catch NullPointerException or any of its ancestors
References
[REF-6] Katrina Tsipenyuk, Brian Chess and Gary McGraw. "Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors". NIST Workshop on Software Security Assurance Tools Techniques and Metrics. NIST. 2005年11月07日.
<https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf>.
[REF-1479] Gregory Larsen, E. Kenneth Hong Fong, David A. Wheeler and Rama S. Moorthy. "State-of-the-Art Resources (SOAR) for Software Vulnerability Detection, Test, and Evaluation". 2014-07.
<https://www.ida.org/-/media/feature/publications/s/st/stateoftheart-resources-soar-for-software-vulnerability-detection-test-and-evaluation/p-5061.ashx>. (URL validated: 2025年09月05日)
Content History
Submissions
Submission Date Submitter Organization
2006年07月19日
(CWE Draft 3, 2006年07月19日) 		7 Pernicious Kingdoms
Modifications
Modification Date Modifier Organization
2025年09月09日
(CWE 4.18, 2025年09月09日) 		CWE Content Team MITRE
updated Detection_Factors, References
2024年02月29日
(CWE 4.14, 2024年02月29日) 		CWE Content Team MITRE
updated Demonstrative_Examples
2023年06月29日 CWE Content Team MITRE
updated Mapping_Notes
2023年04月27日 CWE Content Team MITRE
updated Relationships
2020年02月24日 CWE Content Team MITRE
updated References
2019年01月03日 CWE Content Team MITRE
updated Taxonomy_Mappings
2014年07月30日 CWE Content Team MITRE
updated Detection_Factors, Relationships
2014年06月23日 CWE Content Team MITRE
updated Description, Other_Notes
2012年10月30日 CWE Content Team MITRE
updated Potential_Mitigations
2012年05月11日 CWE Content Team MITRE
updated Relationships
2011年06月01日 CWE Content Team MITRE
updated Common_Consequences, Relationships, Taxonomy_Mappings
2011年03月29日 CWE Content Team MITRE
updated Other_Notes, Relationships
2009年05月27日 CWE Content Team MITRE
updated Demonstrative_Examples
2009年03月10日 CWE Content Team MITRE
updated Relationships
2008年09月08日 CWE Content Team MITRE
updated Relationships, Other_Notes, Taxonomy_Mappings
2008年07月01日 Eric Dalci Cigital
updated Time_of_Introduction
Previous Entry Names
Change Date Previous Entry Name
2008年04月11日 Catch NullPointerException
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Page Last Updated: September 09, 2025

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