CVE-2026-76579
MediumCVSS 4.7Exploitation Probability (EPSS)
Low risk14th percentile - higher than 14% of all known CVEs
Summary
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 allows unauthenticated attackers to inject arbitrary web scripts that execute if they can trick a user into clicking a link. Exploitation requires a validly signed 'esi' value in the GET query string and a separate attacker-controlled 'esi' payload as a POST body field, relying on PHP's default $_REQUEST merge order.
Risk Assessment
The risk includes user session hijacking, data theft, and unauthorized actions in the victim's browser context.
Recommendation
It is recommended to update the plugin to the latest version and educate users about clicking suspicious links.
Other vulnerabilities in LiteSpeed Cache
See all- CVE-2026-84761High
Unauthenticated Server Side Request Forgery (SSRF) in LiteSpeed Cache versions up to 7.9. An attacker can send requests from the server to internal resources without authentication.
- CVE-2026-3129Medium
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via crafted `<img>` tag attributes in all versions up to, and including, 7.7. This is due to a flawed regular expression used to strip `width` and `height` attributes from images when the "Lazy Load Images" and "Add Missing Sizes" features are enabled.
- CVE-2026-18978High
The LiteSpeed Cache plugin for WordPress up to version 7.8.1 is vulnerable to Stored Cross-Site Scripting via Comment Content. Insufficient input sanitization and output escaping allow unauthenticated attackers to inject arbitrary web scripts that execute when a user accesses an injected page. A payload crafted from decimal numeric character references bypasses WordPress's wp_kses sanitization.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS