If a form bean does not extend an ActionForm subclass of the Validator framework, it can expose the application to other weaknesses related to insufficient input validation.

Primary

In order to use the Struts Validator, a form must extend one of the following: ValidatorForm, ValidatorActionForm, DynaValidatorActionForm, and DynaValidatorForm. One of these classes must be extended because the Struts Validator ties in to the application by implementing the validate() method in these classes. Forms derived from the ActionForm and DynaActionForm classes cannot use the Struts Validator.

Implementation

Other
Other
Bypassing the validation framework for a form exposes the application to numerous types of attacks. Unchecked input is an important component of vulnerabilities like cross-site scripting, process control, and SQL injection.

Confidentiality
Integrity
Availability
Other
Other
Although J2EE applications are not generally susceptible to memory corruption attacks, if a J2EE application interfaces with native code that does not perform array bounds checking, an attacker may be able to use an input validation mistake in the J2EE application to launch a buffer overflow attack.

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.)
High

Implementation
Ensure that all forms extend one of the Validation Classes.

In the following Java example the class RegistrationForm is a Struts framework ActionForm Bean that will maintain user information from a registration webpage for an online business site. The user will enter registration data and through the Struts framework the RegistrationForm bean will maintain the user data.

public class RegistrationForm extends org.apache.struts.action.ActionForm {

// private variables for registration formprivate String name;private String email;...
public RegistrationForm() {super();}
// getter and setter methods for private variables...
}

However, the RegistrationForm class extends the Struts ActionForm class which does not allow the RegistrationForm class to use the Struts validator capabilities. When using the Struts framework to maintain user data in an ActionForm Bean, the class should always extend one of the validator classes, ValidatorForm, ValidatorActionForm, DynaValidatorForm or DynaValidatorActionForm. These validator classes provide default validation and the validate method for custom validation for the Bean object to use for validating input data. The following Java example shows the RegistrationForm class extending the ValidatorForm class and implementing the validate method for validating input data.

public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {

// private variables for registration formprivate String name;private String email;...
public RegistrationForm() {super();}
public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {...}
// getter and setter methods for private variables...
}

Note that the ValidatorForm class itself extends the ActionForm class within the Struts framework API.

Struts: Form Bean Does Not Extend Validation Class

SFP24
Tainted input to command

Allowed
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.
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.

7 Pernicious Kingdoms
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Potential_Mitigations, Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities

CWE Content Team
MITRE
2008-11-24
updated Background_Details, Common_Consequences, Other_Notes

CWE Content Team
MITRE
2009-03-10
updated Relationships

CWE Content Team
MITRE
2009-12-28
updated Common_Consequences, Other_Notes

CWE Content Team
MITRE
2010-06-21
updated Demonstrative_Examples

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences

CWE Content Team
MITRE
2012-05-11
updated Relationships

CWE Content Team
MITRE
2012-10-30
updated Potential_Mitigations

CWE Content Team
MITRE
2014-07-30
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2017-11-08
updated Causal_Nature, Relationships

CWE Content Team
MITRE
2020-02-24
updated References, Relationships

CWE Content Team
MITRE
2021-07-20
updated Background_Details

CWE Content Team
MITRE
2023-04-27
updated Detection_Factors, Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Relationships