CVE-2026-3427

MEDIUM 6.4

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

CVSS Score

6.4

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-79
Vendor	yoast
Product	yoast seo – advanced seo with real-time guidance and built-in ai
Published	Mar 22, 2026
Last Updated	Apr 8, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

Affected Versions

yoast / Yoast SEO – Advanced SEO with real-time guidance and built-in AI

0 ≤ 27.1.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

Osvaldo Noe Gonzalez Del Rio