# Improper Handling of Extra Parameters (CWE-235)

The product does not handle or incorrectly handles when the number of parameters, fields, or arguments with the same name exceeds the expected amount.

**Stack:** Python

- Prevalence: Media 2 lenguajes cubiertos
- Impact: Medio Se recomienda revisión
- Prevention: Documentada 2 ejemplos de corrección

**OWASP:** Injection (A03:2021-Injection) - #3

## Description

When applications receive duplicate parameters, they may process them inconsistently, leading to security bypasses or logic errors. Different frameworks may select the first, last, or combine duplicate parameters.

## Prevention

Estrategias de prevención para Improper Handling of Extra Parameters basadas en 1 reglas de detección de Shoulder.

### Python

Explicitly check for and reject duplicate HTTP parameters

## Warning Signs

- [MEDIUM] handling of duplicate HTTP parameters without proper validation

## Consequences

- Eludir mecanismo de protección
- Modificar datos de la aplicación

## Mitigations

- Define y aplica una política para manejar parámetros duplicados
- Rechaza solicitudes con parámetros duplicados sensibles a la seguridad
- Usa frameworks que gestionen los duplicados de forma coherente

## Detection

- Total rules: 2
- Languages: javascript, typescript, python

## Rules by Language

### Python (1 rules)

- **HTTP Parameter Pollution** [MEDIUM]: Detects handling of duplicate HTTP parameters without proper validation.
  - Remediation: Check for duplicate parameters and reject requests with unexpected multiples.

```python
if len(request.args.getlist('param')) > 1:
    return "Duplicate parameters not allowed", 400
```

Learn more: https://shoulder.dev/learn/python/cwe-235/parameter-pollution