Improper validation of integrity check in order replay vulnerability

Due to insufficient validation of a user-controlled key in the `wpcf7_stripe_skip_spam_check` function, unauthenticated attackers can reuse a single Stripe PaymentIntent for multiple transactions. Only the first transaction is processed through Stripe, but the plugin sends a success email message for each transaction, potentially tricking an administrator into fulfilling each order.

This vulnerability affects the following application versions:

• Contact Form 7 5.5
• Contact Form 7 5.5.1
• Contact Form 7 5.5.2
• Contact Form 7 5.5.3
• Contact Form 7 5.5.4
• Contact Form 7 5.5.5
• Contact Form 7 5.5.6
• Contact Form 7 5.5.6.1
• Contact Form 7 5.6
• Contact Form 7 5.6.1
• Contact Form 7 5.6.2
• Contact Form 7 5.6.3
• Contact Form 7 5.6.4
• Contact Form 7 5.7
• Contact Form 7 5.7.1
• Contact Form 7 5.7.2
• Contact Form 7 5.7.3
• Contact Form 7 5.7.4
• Contact Form 7 5.7.5
• Contact Form 7 5.7.5.1
• Contact Form 7 5.7.6
• Contact Form 7 5.7.7
• Contact Form 7 5.8
• Contact Form 7 5.8.1
• Contact Form 7 5.8.2
• Contact Form 7 5.8.3
• Contact Form 7 5.8.4
• Contact Form 7 5.8.5
• Contact Form 7 5.8.6
• Contact Form 7 5.8.7
• Contact Form 7 5.9
• Contact Form 7 5.9.2
• Contact Form 7 5.9.3
• Contact Form 7 5.9.4
• Contact Form 7 5.9.5
• Contact Form 7 5.9.6
• Contact Form 7 5.9.7
• Contact Form 7 5.9.8
• Contact Form 7 6.0
• Contact Form 7 6.0.1
• Contact Form 7 6.0.2
• Contact Form 7 6.0.3
• Contact Form 7 6.0.4
• Contact Form 7 6.0.5