CWE-110 Variant Draft

Struts: Validator Without Form Field

This vulnerability occurs when a Struts application's validation configuration file references form fields that no longer exist in the corresponding ActionForm class. This mismatch indicates…

Definition

What is CWE-110?

This vulnerability occurs when a Struts application's validation configuration file references form fields that no longer exist in the corresponding ActionForm class. This mismatch indicates outdated validation logic that can fail to properly check user input.
This issue commonly arises during maintenance. When a developer modifies an ActionForm by renaming or removing a field but forgets to update the associated validation rules (validator.xml), the validation logic becomes desynchronized. The system may then ignore validation for new or modified fields, potentially allowing malicious or malformed data to pass through. While Java applications themselves are not typically vulnerable to classic buffer overflows, this validation gap becomes critical if the application passes data to native code components (like C/C++ libraries). An attacker could exploit the missing validation to inject unexpected data, potentially triggering a buffer overflow in the native layer and compromising the system.
Real-world impact

Real-world CVEs caused by CWE-110

No public CVE references are linked to this CWE in MITRE's catalog yet.

How attackers exploit it

Step-by-step attacker path

  1. 1

    This example shows an inconsistency between an action form and a validation form. with a third field.

  2. 2

    This first block of code shows an action form that has two fields, startDate and endDate.

  3. 3

    This second block of related code shows a validation form with a third field: scale. The presence of the third field suggests that DateRangeForm was modified without taking validation into account.

Vulnerable code example

Vulnerable Java

This first block of code shows an action form that has two fields, startDate and endDate.

Vulnerable Java 
public class DateRangeForm extends ValidatorForm {
  		String startDate, endDate;
  		public void setStartDate(String startDate) {
  			this.startDate = startDate;
  		}
  		public void setEndDate(String endDate) {
  			this.endDate = endDate;
  		}
  }
Secure code example

Secure pseudo

Secure pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist

How to prevent CWE-110

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Detection signals

How to detect CWE-110

Automated Static Analysis Moderate

To find the issue in the implementation, manual checks or automated static analysis could be applied to the XML configuration files.

Manual Static Analysis Moderate

To find the issue in the implementation, manual checks or automated static analysis could be applied to the XML configuration files.

Plexicus auto-fix

Plexicus auto-detects CWE-110 and opens a fix PR in under 60 seconds.

Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.

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Frequently asked questions

Frequently asked questions

What is CWE-110?

This vulnerability occurs when a Struts application's validation configuration file references form fields that no longer exist in the corresponding ActionForm class. This mismatch indicates outdated validation logic that can fail to properly check user input.

How serious is CWE-110?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-110?

MITRE lists the following affected platforms: Java.

How can I prevent CWE-110?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

How does Plexicus detect and fix CWE-110?

Plexicus's SAST engine matches the data-flow signature for CWE-110 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-110?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/110.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-110

CWE-1164 Parent

Irrelevant Code

Irrelevant code refers to sections of a program that have no impact on its execution, data, or logic. Removing this code would not change…

CWE-107 Sibling

Struts: Unused Validation Form

This vulnerability occurs when a Struts application contains validation form definitions that are no longer linked to any active form or…

CWE-1071 Sibling

Empty Code Block

An empty code block occurs when a section of source code, such as a conditional statement or function body, contains no executable…

CWE-561 Sibling

Dead Code

Dead code refers to sections of a program that can never run during normal execution, effectively making them inactive and unreachable.

CWE-563 Sibling

Assignment to Variable without Use

This vulnerability occurs when a value is stored in a variable, but that variable is never read or used in subsequent code, creating a…

Resources

Further reading

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