CWE-112 Base Borrador

Missing XML Validation

This vulnerability occurs when an application processes XML data from an untrusted source without first validating its structure and content against a defined schema.

Definición

What is CWE-112?

This vulnerability occurs when an application processes XML data from an untrusted source without first validating its structure and content against a defined schema.
When you accept XML without schema validation, you're trusting external data to match your code's expectations. Attackers exploit this gap by sending malformed, oversized, or maliciously crafted XML documents that can trigger parsing errors, consume excessive resources, or enable injection attacks. This fundamentally breaks the security assumption that input will be reasonable and well-formed. Consistently validating XML against a strict DTD or XML Schema is a critical first line of defense. While SAST tools can detect missing validation patterns, Plexicus uses AI to analyze your code flow and suggest precise fixes—like implementing schema validation libraries or hardening parser configurations—saving hours of manual security review and helping prevent this common oversight across your entire application portfolio.
Impacto en el mundo real

Real-world CVEs caused by CWE-112

Todavía no hay CVEs públicos enlazados a esta CWE en el catálogo de MITRE.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    The following code loads and parses an XML file.

  2. 2

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

  3. 3

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

  4. 4

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

Ejemplo de código vulnerable

Vulnerable Java

The following code loads and parses an XML file.

Vulnerable Java 
```
// Read DOM* 
  try {
  ```
  	...
  	DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  	factory.setValidating( false );
  	....
  	c_dom = factory.newDocumentBuilder().parse( xmlFile );
  } catch(Exception ex) {
  	...
  }
Ejemplo de código seguro

Secure pseudo

Seguro 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.
Lista de prevención

How to prevent CWE-112

  • Architecture and Design 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.
Señales de detección

How to detect CWE-112

Automated Static Analysis High

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.)

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-112 y abre un PR de corrección en menos de 60 segundos.

Codex Remedium escanea cada commit, identifica esta debilidad concreta y entrega un pull request listo para revisión con el parche. Sin tickets. Sin traspasos.

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Preguntas frecuentes

Frequently asked questions

¿Qué es CWE-112?

This vulnerability occurs when an application processes XML data from an untrusted source without first validating its structure and content against a defined schema.

¿Qué gravedad tiene CWE-112?

MITRE no ha publicado una calificación de probabilidad de explotación para esta debilidad. Trátala como de impacto medio hasta que tu modelo de amenazas demuestre lo contrario.

¿Qué lenguajes o plataformas se ven afectados por CWE-112?

MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.

¿Cómo puedo prevenir CWE-112?

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.

¿Cómo detecta y corrige Plexicus CWE-112?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-112 en cada commit. Cuando hay coincidencia, nuestro agente Codex Remedium abre un PR de corrección con el código corregido, las pruebas y un resumen de una línea para el revisor.

¿Dónde puedo aprender más sobre CWE-112?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/112.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-112

CWE-1286 Padre

Improper Validation of Syntactic Correctness of Input

This vulnerability occurs when software expects input in a specific, well-structured format but fails to properly check that the incoming…

Recursos

Further reading

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