CWE - CWE-493: Critical Public Variable Without Final Modifier (4.20)
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    CWE-493: Critical Public Variable Without Final Modifier

    Weakness ID: 493
    Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
    Abstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
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    + Description
    The product has a critical public variable that is not final, which allows the variable to be modified to contain unexpected values.
    + Extended Description
    If a field is non-final and public, it can be changed once the value is set by any function that has access to the class which contains the field. This could lead to a vulnerability if other parts of the program make assumptions about the contents of that field.
    + 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

    Modify Application Data

    		Scope: Integrity

    The object could potentially be tampered with.

    Read Application Data

    		Scope: Confidentiality

    The object could potentially allow the object to be read.
    + Potential Mitigations
    Phase(s) Mitigation

    Implementation
    Declare all public fields as final when possible, especially if it is used to maintain internal state of an Applet or of classes used by an Applet. If a field must be public, then perform all appropriate sanity checks before accessing the field from your code.
    + 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. 668 Exposure of Resource to Wrong Sphere
    ParentOf Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. 500 Public Static Field Not Marked Final
    + Background Details
    Mobile code, such as a Java Applet, is code that is transmitted across a network and executed on a remote machine. Because mobile code developers have little if any control of the environment in which their code will execute, special security concerns become relevant. One of the biggest environmental threats results from the risk that the mobile code will run side-by-side with other, potentially malicious, mobile code. Because all of the popular web browsers execute code from multiple sources together in the same JVM, many of the security guidelines for mobile code are focused on preventing manipulation of your objects' state and behavior by adversaries who have access to the same virtual machine where your program is running. Final provides security by only allowing non-mutable objects to be changed after being set. However, only objects which are not extended can be made final.
    + 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

    Class: Object-Oriented (Undetermined Prevalence)

    Java (Undetermined Prevalence)

    C++ (Undetermined Prevalence)

    + Likelihood Of Exploit
    High
    + Demonstrative Examples

    Example 1


    Suppose this WidgetData class is used for an e-commerce web site. The programmer attempts to prevent price-tampering attacks by setting the price of the widget using the constructor.

    (bad code)
    Example Language: Java 
    public final class WidgetData extends Applet {
    public float price;
    ...
    public WidgetData(...) {
    this.price = LookupPrice("MyWidgetType");
    }
    }

    The price field is not final. Even though the value is set by the constructor, it could be modified by anybody that has access to an instance of WidgetData.



    Example 2


    Assume the following code is intended to provide the location of a configuration file that controls execution of the application.

    (bad code)
    Example Language: C++ 
    public string configPath = "/etc/application/config.dat";
    (bad code)
    Example Language: Java 
    public String configPath = new String("/etc/application/config.dat");

    While this field is readable from any function, and thus might allow an information leak of a pathname, a more serious problem is that it can be changed by any function.



    + Weakness Ordinalities
    Ordinality Description
    Primary
    (where the weakness exists independent of other weaknesses)
    + Detection Methods
    Method Details

    Automated Static Analysis
    Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, 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. 485 7PK - Encapsulation
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 849 The CERT Oracle Secure Coding Standard for Java (2011) Chapter 6 - Object Orientation (OBJ)
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1002 SFP Secondary Cluster: Unexpected Entry Points
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1403 Comprehensive Categorization: Exposed Resource
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1440 OWASP Top Ten 2025 Category A05:2025 - Injection
    + 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 Variant 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 Mobile Code: Non-Final Public Field
    CLASP Failure to provide confidentiality for stored data
    The CERT Oracle Secure Coding Standard for Java (2011) OBJ10-J Do not use public static nonfinal variables
    Software Fault Patterns SFP28 Unexpected access points
    + 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. 2005-11-07.
    <https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf>.
    + Content History
    + Submissions
    Submission Date Submitter Organization
    2006-07-19
    (CWE Draft 3, 2006-07-19)     		7 Pernicious Kingdoms
    + Modifications
    Modification Date Modifier Organization
    2025-12-11
    (CWE 4.19, 2025-12-11)     		CWE Content Team MITRE
    updated Applicable_Platforms, Relationships, Weakness_Ordinalities
    2023-06-29
    (CWE 4.12, 2023-06-29)     		CWE Content Team MITRE
    updated Mapping_Notes
    2023-04-27
    (CWE 4.11, 2023-04-27)     		CWE Content Team MITRE
    updated Detection_Factors, Relationships
    2020-02-24
    (CWE 4.0, 2020-02-24)     		CWE Content Team MITRE
    updated References, Relationships
    2019-01-03
    (CWE 3.2, 2019-01-03)     		CWE Content Team MITRE
    updated Taxonomy_Mappings
    2014-07-30
    (CWE 2.8, 2014-07-31)     		CWE Content Team MITRE
    updated Relationships, Taxonomy_Mappings
    2012-05-11
    (CWE 2.2, 2012-05-15)     		CWE Content Team MITRE
    updated Relationships, Taxonomy_Mappings
    2011-06-01
    (CWE 1.13, 2011-06-01)     		CWE Content Team MITRE
    updated Common_Consequences, Relationships, Taxonomy_Mappings
    2009-05-27
    (CWE 1.4, 2009-05-27)     		CWE Content Team MITRE
    updated Background_Details, Demonstrative_Examples, Description, Relationships
    2008-11-24
    (CWE 1.1, 2008-11-25)     		CWE Content Team MITRE
    updated Background_Details, Demonstrative_Examples, Description, Other_Notes, Potential_Mitigations
    2008-09-08
    (CWE 1.0, 2008-09-09)     		CWE Content Team MITRE
    updated Applicable_Platforms, Common_Consequences, Description, Likelihood_of_Exploit, Relationships, Other_Notes, Taxonomy_Mappings
    2008-07-01
    (CWE 1.0, 2008-09-09)     		Eric Dalci Cigital
    updated Time_of_Introduction
    + Previous Entry Names
    Change Date Previous Entry Name
    2008-04-11 Mobile Code: Non-final Public Field
    Page Last Updated: April 30, 2026