CVE-2026-3604
WP SEO Structured Data Schema <= 2.8.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via '_kcseo_ative_tab' Parameter
- 4.9MediumCVSS base score
- 0.23%Exploitation in 30 daysEPSS · top 86% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Wordfence
- 2 months later
· 2 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WordfenceCNA (assigner) | 3.1 | Medium4.9 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N |
| NVDNVD · Deferred | 3.1 | Medium4.9 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.23% · top 86% of all CVEs (11 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.9.
Affected products
kcseopro · WP SEO Structured Data Schema
- affected ≤ 2.8.1
References
References5
- https://www.wordfence.com/threat-intel/vulnerabilities/id/315fbc93-5af3-4fe9-b97a-a09957e54c97?source=cve (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/trunk/lib/classes/KcSeoMetaData.php#L133 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/tags/2.8.1/lib/classes/KcSeoMetaData.php#L133 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/trunk/lib/classes/KcSeoMetaData.php#L177 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/wp-seo-structured-data-schema/tags/2.8.1/lib/classes/KcSeoMetaData.php#L177 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-29391 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-3604)Record last updated .