What’s Vulnerable › Vulnerabilities

CVE-2026-3427: Yoast SEO <= 27.1.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'jsonText' Block Attribute

• Severity: medium (CVSS 6.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-22 · updated 2026-06-17
• Weakness: CWE-79

Description

The Yoast SEO – Advanced SEO with real-time guidance and built-in AI plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the the `jsonText` block attribute in all versions up to, and including, 27.1.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Affected products

• Yoast SEO – Advanced SEO with real-time guidance and built-in AI: through 27.1.1

References

• https://github.com/Yoast/wordpress-seo/pull/23035
• https://plugins.trac.wordpress.org/browser/wordpress-seo/tags/27.0/inc/class-wpseo-utils.php#L915
• https://plugins.trac.wordpress.org/browser/wordpress-seo/tags/27.0/src/generators/schema/howto.php#L125
• https://plugins.trac.wordpress.org/changeset/3475308/wordpress-seo
• https://www.wordfence.com/threat-intel/vulnerabilities/id/fee1fef5-5716-49e0-a04e-d0dae527fcfc?source=cve

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