What’s Vulnerable › Vulnerabilities

CVE-2026-3604: WP SEO Structured Data Schema <= 2.8.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via '_kcseo_ative_tab' Parameter

• Severity: medium (CVSS 4.9 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: 2026-05-12 · updated 2026-06-17
• Weakness: CWE-79

Description

The WP SEO Structured Data Schema plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `_kcseo_ative_tab` parameter in all versions up to, and including, 2.8.1 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

• kcseopro WP SEO Structured Data Schema: through 2.8.1

References

• https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/tags/2.8.1/lib/classes/KcSeoMetaData.php#L133
• https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/tags/2.8.1/lib/classes/KcSeoMetaData.php#L177
• https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/trunk/lib/classes/KcSeoMetaData.php#L133
• https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/trunk/lib/classes/KcSeoMetaData.php#L177
• https://www.wordfence.com/threat-intel/vulnerabilities/id/315fbc93-5af3-4fe9-b97a-a09957e54c97?source=cve

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