CVE-2026-3375LiteSpeed Cache <= 7.7 - Unauthenticated Stored Cross-Site Scripting via QUIC.cloud CCSS/UCSS REST API Endpoints
Updated under an hour ago ()
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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
- 7.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Wordfence
- NVD analysis
- Deferred
- Record last updated
- May 27, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
litespeedtech LiteSpeed Cache litespeedtech:litespeed_cache (from the name) | through 7.7 | CNA record |
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/40fa29f5-525a-4986-91f9-0210a7594e46?source=cve
- https://plugins.trac.wordpress.org/browser/litespeed-cache/trunk/src/rest.cls.php#L108
- 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/router.cls.php#L732
- https://plugins.trac.wordpress.org/changeset/3473912/
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.