LiteSpeed Cache <= 7.7 - Unauthenticated Stored Cross-Site Scripting via QUIC.cloud CCSS/UCSS REST API Endpoints
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | LiteSpeed Cache | <= 7.7 | 7.8 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-79- Platform
- WordPress
- Package
LiteSpeed Cache- Disclosed
- 26.05.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 40fa29f5-525a-4986-91f9-0210a7594e46 - Wordfence Intelligence
Copyright 1999-2026 The MITRE Corporation
Copyright 2012-2026 Defiant Inc.
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Vulnerability history: LiteSpeed Cache
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 23
- First → latest
- 12.2020 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 7
- Medium 15
Disclosures per year
- 2020: 1
- 2021: 2
- 2022: 0
- 2023: 2
- 2024: 11
- 2025: 2
- 2026: 5
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LiteSpeed Cache <= 7.7 - Unauthenticated Stored Cross-Site Scripting via QUIC.cloud CCSS/UCSS REST API Endpoints this entry
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