CVE-2026-76579

LiteSpeed Cache <= 7.9 - Reflected Cross-Site Scripting via ESI 'esi' Parameter

Published Sep 19, 2026 CVSS 3.1 · 4.7 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Litespeedtech
Litespeedtech litespeed Cache
Wordpress
Wordpress wordpress
Vendors & Products Litespeedtech
Litespeedtech litespeed Cache
Wordpress
Wordpress wordpress
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title LiteSpeed Cache <= 7.9 - Reflected Cross-Site Scripting via ESI 'esi' Parameter
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Wordfence
Published
Updated
Sep 19, 2026, 1:51 PM
Reserved
Aug 19, 2026, 2:03 PM
Status
Deferred
Published
Sep 19, 2026, 9:16 AM
Modified
Sep 21, 2026, 1:33 PM