What potential issues can arise from not properly validating POST parameters in PHP?

Potential issues that can arise from not properly validating POST parameters in PHP include security vulnerabilities such as SQL injection, cross-site scripting (XSS), and data manipulation attacks. To solve this issue, it is crucial to sanitize and validate all incoming POST parameters to ensure that they meet the expected format and do not contain malicious code. 

// Example of properly validating POST parameters in PHP
$username = isset($_POST['username']) ? htmlspecialchars($_POST['username']) : '';
$password = isset($_POST['password']) ? htmlspecialchars($_POST['password']) : '';

// Validate username and password
if(empty($username) || empty($password)) {
    // Handle validation error
    echo "Please enter a valid username and password";
    exit;
}

// Further validation and processing of the POST parameters
// ...

Keywords

SQL injection Cross-site scripting (XSS) Data validation Security vulnerabilities Form validation.

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