The CleanTalk WordPress plugin before 6.87 does not prevent unauthenticated, user-supplied comment content from being passed to WordPress's shortcode engine, allowing any visitor to have arbitrary shortcodes registered on the site executed server-side and rendered to every subsequent visitor of the page.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1