CWE-911 Base Incompleto Medium likelihood

Improper Update of Reference Count

This vulnerability occurs when a program uses a reference counter to track resource usage but fails to update the count correctly, either by missing an update or applying an incorrect value.

Definición

What is CWE-911?

This vulnerability occurs when a program uses a reference counter to track resource usage but fails to update the count correctly, either by missing an update or applying an incorrect value.
Reference counting is a common technique for managing resources like memory blocks or file handles. The system tracks how many active pointers or handles refer to a resource, and the resource is only freed when this count drops to zero. If the count is accidentally decremented too early, the resource can be prematurely released while still in use, leading to crashes or use-after-free errors. Conversely, if the reference count isn't decremented when a reference is removed, the count never reaches zero. This creates a resource leak, where unused memory or handles are never reclaimed. Over time, these leaks degrade performance and can exhaust system resources, causing instability or denial of service.
Impacto en el mundo real

Real-world CVEs caused by CWE-911

  • CVE-2002-0574

    chain: reference count is not decremented, leading to memory leak in OS by sending ICMP packets.

  • CVE-2004-0114

    Reference count for shared memory not decremented when a function fails, potentially allowing unprivileged users to read kernel memory.

  • CVE-2006-3741

    chain: improper reference count tracking leads to file descriptor consumption

  • CVE-2007-1383

    chain: integer overflow in reference counter causes the same variable to be destroyed twice.

  • CVE-2007-1700

    Incorrect reference count calculation leads to improper object destruction and code execution.

  • CVE-2008-2136

    chain: incorrect update of reference count leads to memory leak.

  • CVE-2008-2785

    chain/composite: use of incorrect data type for a reference counter allows an overflow of the counter, leading to a free of memory that is still in use.

  • CVE-2008-5410

    Improper reference counting leads to failure of cryptographic operations.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    Identifica una ruta de código que maneje entrada no confiable sin validación.

  2. 2

    Crea un payload que ejercite el comportamiento inseguro — inyección, traversal, overflow o abuso de lógica.

  3. 3

    Envía el payload a través de una solicitud normal y observa la reacción de la aplicación.

  4. 4

    Itera hasta que la respuesta filtre datos, ejecute código del atacante o escale privilegios.

Ejemplo de código vulnerable

Vulnerable pseudo

MITRE no ha publicado un ejemplo de código para esta CWE. El patrón siguiente es ilustrativo — consulta Recursos para referencias canónicas.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
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-911

  • 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.
Señales de detección

How to detect CWE-911

SAST High

Ejecuta análisis estático (SAST) sobre el código buscando el patrón inseguro en el flujo de datos.

DAST Moderate

Ejecuta pruebas dinámicas de seguridad de aplicaciones (DAST) contra el endpoint en vivo.

Runtime Moderate

Vigila los logs en tiempo de ejecución para detectar trazas de excepción inusuales, entradas malformadas o intentos de bypass de autorización.

Code review Moderate

Revisión de código: marca cualquier código nuevo que maneje entrada desde esta superficie sin usar los helpers validados del framework.

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-911 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.

Solicitar demo Probar Plexicus gratis
Preguntas frecuentes

Frequently asked questions

¿Qué es CWE-911?

This vulnerability occurs when a program uses a reference counter to track resource usage but fails to update the count correctly, either by missing an update or applying an incorrect value.

¿Qué gravedad tiene CWE-911?

MITRE califica la probabilidad de explotación como Media — la explotación es realista pero suele requerir condiciones específicas.

¿Qué lenguajes o plataformas se ven afectados por CWE-911?

MITRE lists the following affected platforms: C, C++.

¿Cómo puedo prevenir CWE-911?

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.

¿Cómo detecta y corrige Plexicus CWE-911?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-911 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-911?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/911.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-911

CWE-664 Padre

Improper Control of a Resource Through its Lifetime

This vulnerability occurs when software fails to properly manage a resource throughout its entire lifecycle—from creation and active use…

CWE-118 Hermano

Incorrect Access of Indexable Resource ('Range Error')

This vulnerability occurs when software fails to properly check the boundaries of an indexed resource, like an array, buffer, or file,…

CWE-1229 Hermano

Creation of Emergent Resource

This vulnerability occurs when a system's normal operations unintentionally create new, exploitable resources that attackers can use to…

CWE-1250 Hermano

Improper Preservation of Consistency Between Independent Representations of Shared State

This vulnerability occurs when a system with multiple independent components (like distributed services or separate hardware units) each…

CWE-1329 Hermano

Reliance on Component That is Not Updateable

This vulnerability occurs when a product depends on a component that cannot be updated or patched to fix security flaws or critical bugs.

CWE-221 Hermano

Information Loss or Omission

This weakness occurs when an application fails to log critical security events or records them inaccurately, which can misguide security…

CWE-372 Hermano

Incomplete Internal State Distinction

This vulnerability occurs when an application fails to accurately track its own operational state. The system incorrectly assumes it's in…

CWE-400 Hermano

Uncontrolled Resource Consumption

This vulnerability occurs when an application fails to properly manage a finite resource, allowing an attacker to exhaust it and cause a…

CWE-404 Hermano

Improper Resource Shutdown or Release

This vulnerability occurs when a program fails to properly close or release a system resource—like a file handle, database connection, or…

Recursos

Further reading

Listo cuando tú lo estés

Deja de pagar por desarrollador.
Empieza a cerrar el bucle.

Plexicus es el ASPM nativo de IA que escanea, filtra, corrige, pentestea y explica — de forma autónoma. Desarrolladores ilimitados, repos ilimitados, acciones de IA de uso justo. Nivel gratuito real, €269/mo anual cuando estés listo.

Comenzar gratis Reservar una demo