CWE - CWE-112: Missing XML Validation (4.18)

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CWE Glossary Definition

CWE-112: Missing XML Validation

Weakness ID: 112

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 accepts XML from an untrusted source but does not validate the XML against the proper schema.

Extended Description

Most successful attacks begin with a violation of the programmer's assumptions. By accepting an XML document without validating it against a DTD or XML schema, the programmer leaves a door open for attackers to provide unexpected, unreasonable, or malicious input.

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
Unexpected State	Scope: Integrity

Potential Mitigations

Phase(s)	Mitigation
Architecture and Design	Strategy: Input Validation Always validate XML input against a known XML Schema or DTD. It is not possible for an XML parser to validate all aspects of a document's content because a parser cannot understand the complete semantics of the data. However, a parser can do a complete and thorough job of checking the document's structure and therefore guarantee to the code that processes the document that the content is well-formed.

Phase(s)

Mitigation

Architecture and Design

Strategy: Input Validation

Always validate XML input against a known XML Schema or DTD.

It is not possible for an XML parser to validate all aspects of a document's content because a parser cannot understand the complete semantics of the data. However, a parser can do a complete and thorough job of checking the document's structure and therefore guarantee to the code that processes the document that the content is well-formed.

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	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.	1286	Improper Validation of Syntactic Correctness of Input

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.	1215	Data Validation Issues

Relevant to the view "Seven Pernicious Kingdoms" (View-700)

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.	20	Improper Input Validation

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: Not Language-Specific (Undetermined Prevalence)

Demonstrative Examples

Example 1

The following code loads and parses an XML file.

(bad code)

Example Language: Java

// Read DOM
try {

...
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating( false );
....
c_dom = factory.newDocumentBuilder().parse( xmlFile );

} catch(Exception ex) {

...

}

The XML file is loaded without validating it against a known XML Schema or DTD.

Example 2

The following code creates a DocumentBuilder object to be used in building an XML document.

(bad code)

Example Language: Java

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
builderFactory.setNamespaceAware(true);
DocumentBuilder builder = builderFactory.newDocumentBuilder();

The DocumentBuilder object does not validate an XML document against a schema, making it possible to create an invalid XML document.

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

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.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.	1406	Comprehensive Categorization: Improper Input Validation

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.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
7 Pernicious Kingdoms	Missing XML Validation
Software Fault Patterns	SFP24	Tainted input to command

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-230	Serialized Data with Nested Payloads
CAPEC-231	Oversized Serialized Data Payloads

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年11月07日.
<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年07月19日 (CWE Draft 3, 2006年07月19日)	7 Pernicious Kingdoms
2006年07月19日 (CWE Draft 3, 2006年07月19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 Detection_Factors, Relationships
2023年01月31日	CWE Content Team	MITRE
2023年01月31日	updated Description
2020年06月25日	CWE Content Team	MITRE
2020年06月25日	updated Relationships
2020年02月24日	CWE Content Team	MITRE
2020年02月24日	updated References, Related_Attack_Patterns, Relationships
2019年01月03日	CWE Content Team	MITRE
2019年01月03日	updated Relationships
2017年11月08日	CWE Content Team	MITRE
2017年11月08日	updated Applicable_Platforms, Causal_Nature, Relationships
2017年01月19日	CWE Content Team	MITRE
2017年01月19日	updated Relationships
2014年07月30日	CWE Content Team	MITRE
2014年07月30日	updated Demonstrative_Examples, Relationships, Taxonomy_Mappings
2014年06月23日	CWE Content Team	MITRE
2014年06月23日	updated Demonstrative_Examples, Other_Notes, Potential_Mitigations
2014年02月18日	CWE Content Team	MITRE
2014年02月18日	updated Related_Attack_Patterns
2013年02月21日	CWE Content Team	MITRE
2013年02月21日	updated Potential_Mitigations
2012年05月11日	CWE Content Team	MITRE
2012年05月11日	updated Relationships
2011年06月27日	CWE Content Team	MITRE
2011年06月27日	updated Common_Consequences
2011年06月01日	CWE Content Team	MITRE
2011年06月01日	updated Common_Consequences
2009年10月29日	CWE Content Team	MITRE
2009年10月29日	updated Description
2009年05月27日	CWE Content Team	MITRE
2009年05月27日	updated Demonstrative_Examples
2008年11月24日	CWE Content Team	MITRE
2008年11月24日	updated Description, Other_Notes
2008年09月08日	CWE Content Team	MITRE
2008年09月08日	updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008年07月01日	Eric Dalci	Cigital
2008年07月01日	updated Demonstrative_Example, Potential_Mitigations, Time_of_Introduction
2008年07月01日	Sean Eidemiller	Cigital
2008年07月01日	added/updated demonstrative examples

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Page Last Updated: September 09, 2025

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