The YMC Filter plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the 'post_title' parameter in all versions up to, and including, 3.12.19 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The autocomplete REST endpoint is registered with a permission callback that unconditionally returns true, meaning any site visitor — including unauthenticated users — can trigger the payload simply by typing in the YMC filter search box, while only Author-level access is required to store it.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic 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
Weakness Type (CWE)
Vulnerable Products
wssoffice21:ymc filter
References 7
https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/a…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/s…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/s…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/s…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.20/ymc2/s…
security@wordfence.com
https://wordpress.org/plugins/ymc-smart-filter
security@wordfence.com
https://www.wordfence.com/threat-intel/vulnerabilities/id/27cfa62d-ba16-4344-be…
security@wordfence.com