The Relevanssi – A Better Search plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 4.28.5 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the site to have both the comment indexing and comment highlighting options enabled, and the payload only fires when a visitor reaches a singular page via a Relevanssi search-result permalink carrying the highlight query parameter.
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
Weakness Type (CWE)
Vulnerable Products
comesio:relevanssi – a better search
References 8
https://github.com/msaari/relevanssi/commit/b0324957b27e2dfc2aa116c96dcf578fbec…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/relevanssi/tags/4.28.5/lib/common.ph…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/relevanssi/tags/4.28.5/lib/excerpts-…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/relevanssi/tags/4.28.5/lib/excerpts-…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/relevanssi/tags/4.28.5/lib/excerpts-…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/relevanssi/tags/4.28.5/lib/init.php#…
security@wordfence.com
https://plugins.trac.wordpress.org/changeset?reponame=&new=3767703%40relevanssi…
security@wordfence.com
https://www.wordfence.com/threat-intel/vulnerabilities/id/442403ae-9011-4373-a3…
security@wordfence.com