CVE-2026-19760 WP Fastest Cache <= 1.5.0 - Unauthenticated Stored Cross-Site Scripting via HTTP Host Header
Unauthenticated attackers can inject scripts via HTTP Host header in WP Fastest Cache, requiring Polylang and Combine JS enabled, leading to stored XSS.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-19760?
CVE-2026-19760 is a high-severity cross-site scripting vulnerability in emrevona WP Fastest Cache – WordPress Cache Plugin, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The WP Fastest Cache – WordPress Cache Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via HTTP Host Header in all versions up to, and including, 1.5.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the Polylang or Polylang Pro plugin to be active and the Combine JS option to be enabled, as these conditions trigger the vulnerable Host-header-to-URL code path that writes attacker-controlled script src values into the shared page-cache file served to all subsequent visitors.
Weakness: CWE-79
Which versions are affected by CVE-2026-19760?
How do I fix CVE-2026-19760?
No fix has been published for CVE-2026-19760 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-19760 being exploited?
There is no known exploitation of CVE-2026-19760 in the wild and no public exploit code.
Sources
Also known as GHSA-q9vw-j254-6x3w.