Question about the QR code. Hackers?

Question

PHP

I have a question. There is a web application where there is a user's personal account. So one of the users began to complain that the QR code on the Google browser gives a normal result (card number), and in the Yandex browser its code is constantly replaced by other clients from the database !!! Although the QR code is stored on login in a cookie (visitors usually don't log out of the app). The same card number is duplicated in the line below (the same variable is used as for generating the QR code). So this bottom line is exactly the same in all browsers! What could it be? There is no database access whatsoever!

$text_for_qr_code = $_COOKIE["discountCardNumber"] . "";

QRcode::png($text_for_qr_code, 'test.png', "L", 6, 4);

<p><span>Номер карты:</span> <?php echo $_COOKIE["discountCardNumber"]; ?></p>

Answer 1

test.pngthe picture is cached somewhere and displayed to everyone. Generate the image as a base64 string and paste it as src to the img tag.