Joomla Extension - j2commerce.com - Unescaped request data reflected into PayPal notify redirect...

Joomla Extension - j2commerce.com - Unescaped request data reflected into PayPal notify redirect in J2Store 1.0.0-3.3.2, 4.0.0-4.0.22, 4.1.0-4.1.7 - A crafted link to the paypal notify endpoint, if followed by a victim's browser (or an automated system that fetches it), causes the resulting redirect to com_j2store's checkout controller to carry attacker-chosen query parameters instead of only the intended view=checkout&task=confirmPayment&orderpayment_type=...&paction=process set — parameter injection/smuggling into that follow-up request. This requires a victim to load the crafted link (UI:R/UI:P); it does not by itself grant an unauthenticated attacker anything they could not already obtain by requesting the target com_j2store URL directly with their own parameters.