What are the consequences of CWE-109?

Exploiting CWE-109 can lead to: Bypass Protection Mechanism.

Variant weakness

Draft

CWE-109: Struts: Validator Turned Off

Automatic filtering via a Struts bean has been turned off, which disables the Struts Validator and custom validation logic. This exposes the application to other weaknesses related to insufficient input validation.

Last updated May 1, 2026

Recorded CVEs

With this primary weakness

KEVs

In the CISA KEV catalog

Not rated

Likelihood of exploit

Per MITRE

Variant

Abstraction

MITRE classification

Overview

CWE-109 (Struts: Validator Turned Off) is a variant-level software weakness catalogued by MITRE in the Common Weakness Enumeration (CWE). It describes a recurring type of mistake that can lead to exploitable security vulnerabilities.

Common consequences

What can happen when CWE-109 is exploited.

Bypass Protection Mechanism

Affects: Access Control

How it happens

When it is introduced

Typically introduced during these phases of the software lifecycle.

Implementation

Applies to

Languages

Java

How to prevent it

Practical mitigations for CWE-109, grouped by where in the lifecycle they apply.

Implementation

Ensure that an action form mapping enables validation. Set the validate field to true.

Code examples

Illustrative examples from MITRE showing how the weakness appears in code.

This mapping defines an action for a download form:

Vulnerable example

xml

<action path="/download"

This mapping has disabled validation. Disabling validation exposes this action to numerous types of attacks.

Terminology & mappings

Mapped taxonomies

7 Pernicious Kingdoms: Struts: Validator Turned Off
Software Fault Patterns: Tainted input to command (SFP24)

Frequently asked questions

Common questions about CWE-109.

What is CWE-109?: Automatic filtering via a Struts bean has been turned off, which disables the Struts Validator and custom validation logic. This exposes the application to other weaknesses related to insufficient input validation.
How do you prevent CWE-109?: Ensure that an action form mapping enables validation. Set the validate field to true.
What are the consequences of CWE-109?: Exploiting CWE-109 can lead to: Bypass Protection Mechanism.

References

Weakness data is sourced from the MITRE CWE catalog (v4.20). CVE associations are aggregated and kept current by RadicalNotion.AI.

Stay ahead of CWE-109

Get alerted the moment a new CWE-109 vulnerability affects your stack, with AI-written analysis, severity context, and remediation guidance.

Start free See pricing