Describe CVE-2021-24559.
What is CVE-2021-24559?
The Qyrr WordPress plugin before 0.7 does not escape the data-uri of the QR Code when outputting it in a src attribute, allowing for Cross-Site Scripting attacks. Furthermore, the data_uri_to_meta AJAX action, available to all authenticated users, only had a CSRF check in place, with the nonce available to users with a role as low as Contributor allowing any user with such role (and above) to set a malicious data-uri in arbitrary QR Code posts, leading to a Stored Cross-Site Scripting issue..