The LiteSpeed Cache plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'esi' parameter in all versions up to, and including, 7.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Exploitation requires that the attacker supply a validly signed 'esi' value in the GET query string while submitting a separate attacker-controlled 'esi' payload as a POST body field, relying on PHP's default $_REQUEST merge order to have the POST value take precedence at the point of execution.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required
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
litespeedtech:litespeed cache
References 7
https://plugins.trac.wordpress.org/browser/litespeed-cache/tags/7.9/src/esi.cls…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/litespeed-cache/tags/7.9/src/esi.cls…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/litespeed-cache/tags/7.9/src/esi.cls…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/litespeed-cache/tags/7.9/src/esi.cls…
security@wordfence.com
https://plugins.trac.wordpress.org/changeset/3676856/litespeed-cache/trunk/src/…
security@wordfence.com
https://plugins.trac.wordpress.org/changeset?reponame=&new=3676856%40litespeed-…
security@wordfence.com
https://www.wordfence.com/threat-intel/vulnerabilities/id/ba236f86-0434-4030-8e…
security@wordfence.com