CVE-2021-24153: Yoast Seo

Medium severity, CVSS 5.4. EPSS: 1.1% chance of exploitation in the next 30 days.

A Stored Cross-Site Scripting vulnerability was discovered in the Yoast SEO WordPress plugin before 3.4.1, which had built-in blacklist filters which were blacklisting Parenthesis as well as several functions such as alert but bypasses were found.

Affected products

• Yoast Yoast Seo: before 3.4.1 (fixed in 3.4.1)

Published 2021-04-05. Last modified 2026-06-17.