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.)
CWE-674 Clase Borrador
Uncontrolled Recursion
This vulnerability occurs when an application fails to limit how deeply a function can call itself. Without proper controls, this uncontrolled recursion can exhaust system resources like memory or…
Definición
What is CWE-674?
This vulnerability occurs when an application fails to limit how deeply a function can call itself. Without proper controls, this uncontrolled recursion can exhaust system resources like memory or stack space, leading to crashes or denial-of-service.
Uncontrolled recursion happens when a recursive function lacks a proper termination condition or depth limit. This allows it to run indefinitely or until it consumes all available stack memory, causing a stack overflow. Common triggers include processing deeply nested user input (like XML/JSON), complex graph traversals, or mathematical sequences without safety checks. Developers should always implement a maximum recursion depth or convert recursive logic to iterative loops for critical operations.
Detecting these flaws manually in a large codebase is challenging, as recursion paths can be complex. While SAST tools can identify the risky pattern, Plexicus uses AI to not only flag the issue but also generate specific, safe code fixes—such as adding depth counters or suggesting iterative alternatives—saving significant manual review and remediation time.
Impacto en el mundo real
Real-world CVEs caused by CWE-674
-
Deeply nested arrays trigger stack exhaustion.
-
Self-referencing pointers create infinite loop and resultant stack exhaustion.
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Javascript application accidentally changes input in a way that prevents a recursive call from detecting an exit condition.
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An attempt to recover a corrupted XML file infinite recursion protection counter was not always incremented missing the exit condition.
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USB-audio driver's descriptor code parsing allows unlimited recursion leading to stack exhaustion.
Cómo lo explotan los atacantes
Ruta del atacante paso a paso
- 1
Identifica una ruta de código que maneje entrada no confiable sin validación.
- 2
Crea un payload que ejercite el comportamiento inseguro — inyección, traversal, overflow o abuso de lógica.
- 3
Envía el payload a través de una solicitud normal y observa la reacción de la aplicación.
- 4
Itera hasta que la respuesta filtre datos, ejecute código del atacante o escale privilegios.
Ejemplo de código vulnerable
Vulnerable C
In this example a mistake exists in the code where the exit condition contained in flg is never called. This results in the function calling itself over and over again until the stack is exhausted.
void do_something_recursive (int flg)
{
```
... // Do some real work here, but the value of flg is unmodified
if (flg) { do_something_recursive (flg); } // flg is never modified so it is always TRUE - this call will continue until the stack explodes
}
int flag = 1; // Set to TRUE
do_something_recursive (flag); Ejemplo de código seguro
Secure C
Note that the only difference between the Good and Bad examples is that the recursion flag will change value and cause the recursive call to return.
void do_something_recursive (int flg)
{
```
... // Do some real work here
// Modify value of flg on done condition
if (flg) { do_something_recursive (flg); } // returns when flg changes to 0
}
int flag = 1; // Set to TRUE
do_something_recursive (flag); 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-674
- Implementation Ensure an end condition will be reached under all logic conditions. The end condition may include testing against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action.
- Implementation Increase the stack size.
Señales de detección
How to detect CWE-674
CWE-674
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Preguntas frecuentes ¿Qué es CWE-674?
¿Qué gravedad tiene CWE-674?
¿Qué lenguajes o plataformas se ven afectados por CWE-674?
¿Cómo puedo prevenir CWE-674?
¿Cómo detecta y corrige Plexicus CWE-674?
¿Dónde puedo aprender más sobre CWE-674?
Frequently asked questions
¿Qué es CWE-674?
This vulnerability occurs when an application fails to limit how deeply a function can call itself. Without proper controls, this uncontrolled recursion can exhaust system resources like memory or stack space, leading to crashes or denial-of-service.
¿Qué gravedad tiene CWE-674?
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-674?
MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.
¿Cómo puedo prevenir CWE-674?
Ensure an end condition will be reached under all logic conditions. The end condition may include testing against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action. Increase the stack size.
¿Cómo detecta y corrige Plexicus CWE-674?
El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-674 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-674?
MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/674.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.
Debilidades relacionadas
Weaknesses related to CWE-674
CWE-834 Padre
Excessive Iteration
This vulnerability occurs when a program runs a loop too many times because it lacks proper limits on its iterations.
CWE-1322 Hermano
Use of Blocking Code in Single-threaded, Non-blocking Context
This vulnerability occurs when an application designed to be single-threaded and non-blocking, for performance and scalability,…
CWE-835 Hermano
Loop with Unreachable Exit Condition ('Infinite Loop')
An infinite loop occurs when a program's iteration logic contains an exit condition that can never be satisfied, causing the loop to run…
CWE-776 Hijo
Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
This vulnerability occurs when an XML parser allows Document Type Definitions (DTDs) to contain recursively defined entities without…
¿Listo para validar lo que importa?
Listo para validar lo que importa.
Plexicus es Proof-Driven AppSec: hallazgos validados, comprensión contextual y remediación revisada — anclada en evidencia, acotada contigo.