CVE-2026-16618: Unknown Improve Seo

Critical severity, CVSS 9.8. EPSS: 0.8% chance of exploitation in the next 30 days.

The Improve SEO WordPress plugin through 2.0.11 does not properly validate uploaded files, checking only the file content type while writing the file with the attacker-supplied extension into a publicly accessible directory, allowing unauthenticated users to upload executable PHP files and achieve remote code execution.

Affected products

• Unknown Improve Seo: up to and including 2.0.11

Published 2026-08-04. Last modified 2026-08-26.