CVE-2026-3375

Description

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the /wp-json/litespeed/v1/notify_ccss and /wp-json/litespeed/v1/notify_ucss REST API endpoints in all versions up to, and including, 7.7. These endpoints accept CSS content from QUIC.cloud callback notifications and store it to disk without sanitization. The stored content is later rendered inline frontend page loads without output escaping. The access control protecting these endpoints is IP-based validation that can potentially be bypassed when the WordPress site is deployed behind a reverse proxy, load balancer, or CDN with certain configurations. This makes it possible for unauthenticated attackers, under certain conditions, to inject arbitrary JavaScript into CCSS/UCSS content.

CVSS v3.1 Score

7.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0007

Probability of exploitation

0.20%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/cloud.cls.php#L2085 https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/css.cls.php#L401 https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/css.cls.php#L595 https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/optimize.cls.php#L477 https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/rest.cls.php#L108 https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/router.cls.php#L732 https://plugins.trac.wordpress.org/changeset/3473912/ https://www.wordfence.com/threat-intel/vulnerabilities/id/40fa29f5-525a-4986-91f9-0210a7594e46?source=cve

Frequently Asked Questions

What is CVE-2026-3375? +

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the /wp-json/litespeed/v1/notify_ccss and /wp-json/litespeed/v1/notify_ucss REST API endpoints in all versions up to, and including, 7.7. These endpoints accept CSS content from QUIC.cloud callback notifications and store it to disk without sanitization. The stored content is later rendered inline frontend page loads without output escaping. The access control protecting these endpoints is IP-based validation that can potentially be bypassed when the WordPress site is deployed behind a reverse proxy, load balancer, or CDN with certain configurations. This makes it possible for unauthenticated attackers, under certain conditions, to inject arbitrary JavaScript into CCSS/UCSS content. It has a CVSS v3.1 base score of 7.2 (HIGH).

How severe is CVE-2026-3375? +

CVE-2026-3375 has a CVSS v3.1 score of 7.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0007, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-3375? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-40282

WeGIA is a web manager for charitable institutions. In versions prior to 3.6.10, a Stored Cross-Site Scripting (XSS) vulnerability allows …

CVE-2026-3317

Reflected Cross-Site Scripting (XSS) vulnerability in Navigate Content Management System. The vulnerability is present in the '/blog' endpoint because user …

CVE-2025-10354

Cross-Site Scripting (XSS) vulnerability reflected in Semantic MediaWiki. This vulnerability allows an attacker to execute JavaScript code in the victim's …

CVE-2026-41456

Bludit CMS prior to commit 6732dde contains a reflected cross-site scripting vulnerability in the search plugin that allows unauthenticated attackers …

CVE-2026-40872

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover …

CVE-2026-40878

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the mailcow web interface …