High severity · published Aug 28, 2026
CVE-2026-18978
LiteSpeed Cache <= 7.8.1 - Unauthenticated Stored Cross-Site Scripting via Comment Content
7.2
CVSS
0.4%
EPSS
No
On KEV
Description
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 7.8.1 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. A comment payload crafted exclusively from decimal numeric character references (e.g. &#34;, &#60;, &#62;) placed inside an allowed element such as &lt;code&gt; bypasses WordPress's wp_kses sanitization, as kses does not treat a data-settings="..." substring within text content as an HTML attribute, allowing the malicious payload to reach the vulnerable function. For this to be exploitable, the site must allow users with previously approved comments to write new comments, and the require_name_email setting must be disabled.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LC
LiteSpeed Cache · litespeedtech
through 7.8.1 · source: vendor
Affected product
LC
LiteSpeed Cache
litespeedtech
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