Although a security update has been released since December 7, 2021 to fix two SEO WordPress plugins, recent revelations from download statistics showed that more than 820,000 websites using the plugin have not yet installed the update.
The two bugs in question, a critical Authenticated Privilege Escalation bug (CVE-2021-25036) and a high severity Authenticated SQL Injection (CVE-2021-25037) are considered very dangerous.
With the flaws, attackers only need low-level permissions such as Subscriber (a default WordPress user role that allows registered users to comment on articles published on WordPress sites).
As subscribers, attackers can exploit CVE-2021-25036 to elevate their privileges. After this, they gain remote code execution on vulnerable websites and take over completely.
In order to prevent such a takeover, WordPress admins using All in One SEO versions impacted by the flaw (4.0.0 to 220.127.116.11) and are yet to install the 18.104.22.168 patch are advised to do so immediately.
For more information, read the original story in BleepingComputer.