What is CVE-2026-3375?

CVE-2026-3375 is a high-severity vulnerability in Litespeedtech Litespeed Cache, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-05-27.

How severe is CVE-2026-3375?

High severity. CVSS v3 base score is 7.2 out of 10.

XSS in Litespeedtech Litespeed Cache

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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.004 (29.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

Affected products

Litespeedtech Litespeed Cache — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

Frequently asked questions

What is CVE-2026-3375?: CVE-2026-3375 is a high-severity vulnerability in Litespeedtech Litespeed Cache, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-05-27.
How severe is CVE-2026-3375?: High severity. CVSS v3 base score is 7.2 out of 10.