CWE - CWE-767: Access to Critical Private Variable via Public Method (4.18)

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CWE Glossary Definition

CWE-767: Access to Critical Private Variable via Public Method

Weakness ID: 767

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

The product defines a public method that reads or modifies a private variable.

Extended Description

If an attacker modifies the variable to contain unexpected values, this could violate assumptions from other parts of the code. Additionally, if an attacker can read the private variable, it may expose sensitive information or make it easier to launch further attacks.

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; Other	Scope: Integrity, Other

Potential Mitigations

Phase(s)	Mitigation
Implementation	Use class accessor and mutator methods appropriately. Perform validation when accepting data from a public method that is intended to modify a critical private variable. Also be sure that appropriate access controls are being applied when a public method interfaces with critical data.

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

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.	275	Permission Issues

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

C++ (Undetermined Prevalence)

C# (Undetermined Prevalence)

Java (Undetermined Prevalence)

Demonstrative Examples

Example 1

The following example declares a critical variable to be private, and then allows the variable to be modified by public methods.

(bad code)

Example Language: C++

private: float price;
public: void changePrice(float newPrice) {

price = newPrice;

}

Example 2

The following example could be used to implement a user forum where a single user (UID) can switch between multiple profiles (PID).

(bad code)

Example Language: Java

public class Client {

private int UID;
public int PID;
private String userName;
public Client(String userName){

PID = getDefaultProfileID();
UID = mapUserNametoUID( userName );
this.userName = userName;

}
public void setPID(int ID) {

UID = ID;

}

The programmer implemented setPID with the intention of modifying the PID variable, but due to a typo. accidentally specified the critical variable UID instead. If the program allows profile IDs to be between 1 and 10, but a UID of 1 means the user is treated as an admin, then a user could gain administrative privileges as a result of this typo.

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.	963	SFP Secondary Cluster: Exposed Data
MemberOf	CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.	1184	SEI CERT Perl Coding Standard - Guidelines 06. Object-Oriented Programming (OOP)
MemberOf	CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.	1403	Comprehensive Categorization: Exposed Resource

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.

Notes

Maintenance

This entry is closely associated with access control for public methods. If the public methods are restricted with proper access controls, then the information in the private variable will not be exposed to unexpected parties. There may be chaining or composite relationships between improper access controls and this weakness.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP	Failure to protect stored data from modification
Software Fault Patterns	SFP23	Exposed Data
SEI CERT Perl Coding Standard	OOP31-PL	Imprecise	Do not access private variables or subroutines in other packages

Content History

Submissions
Submission Date	Submitter	Organization
2009年03月03日 (CWE 1.4, 2009年05月27日)	CWE Content Team	MITRE
2009年03月03日 (CWE 1.4, 2009年05月27日)
Modifications
Modification Date	Modifier	Organization
2023年06月29日	CWE Content Team	MITRE
2023年06月29日	updated Mapping_Notes
2023年04月27日	CWE Content Team	MITRE
2023年04月27日	updated Relationships, Time_of_Introduction, Type
2023年01月31日	CWE Content Team	MITRE
2023年01月31日	updated Description
2021年03月15日	CWE Content Team	MITRE
2021年03月15日	updated Relationships
2020年02月24日	CWE Content Team	MITRE
2020年02月24日	updated Relationships
2019年01月03日	CWE Content Team	MITRE
2019年01月03日	updated Taxonomy_Mappings
2017年11月08日	CWE Content Team	MITRE
2017年11月08日	updated Likelihood_of_Exploit, Relationships, Taxonomy_Mappings
2014年07月30日	CWE Content Team	MITRE
2014年07月30日	updated Relationships, Taxonomy_Mappings
2012年05月11日	CWE Content Team	MITRE
2012年05月11日	updated Relationships
2011年06月01日	CWE Content Team	MITRE
2011年06月01日	updated Common_Consequences

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Page Last Updated: September 09, 2025

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