# CVE-2026-3375: LiteSpeed Cache <= 7.7 - Unauthenticated Stored Cross-Site Scripting via QUIC.cloud CCSS/UCSS REST API Endpoints

> Unauthenticated attackers can inject arbitrary JavaScript via REST API endpoints in the LiteSpeed Cache WordPress plugin, potentially leading to code execution or account takeover.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 May 2026
- **Updated:** 27 May 2026
- **Also known as:** GHSA-hf4x-3pgg-4r9c

## What is CVE-2026-3375?

CVE-2026-3375 is a high-severity cross-site scripting vulnerability in litespeedtech LiteSpeed Cache, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-3375?


## How do I fix CVE-2026-3375?

No fix has been published for CVE-2026-3375 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3375 being exploited?

There is no known exploitation of CVE-2026-3375 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3375 and fix it if it is affected.

What it is: CVE-2026-3375 is a high-severity cross-site scripting vulnerability in litespeedtech LiteSpeed Cache, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-3375 in the wild and no public exploit code.

Affected product: litespeedtech LiteSpeed Cache. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-3375/ (Markdown: https://insights.sbomify.com/CVE-2026-3375/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3375
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3375
- OSV: https://osv.dev/vulnerability/CVE-2026-3375

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3375/
Summaries are generated and may contain mistakes; the official description above is the record.