CVE-2026-3427: Yoast SEO <= 27.1.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'jsonText' Block Attribute
Vulnerability summary
CVE-2026-3427 is a medium (CVSS 6.4) Cross-site Scripting vulnerability in wordpress wordpress-seo. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 26.7% of scored vulnerabilities. Fixed in 27.2.
Timeline
- 22-03-2026PublishedVulnerability first disclosed.
- 08-04-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- NVDNIST6.4MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- wordfenceSource6.4MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
EPSS trend
Probability
0.34%
Chance of exploitation in the next 30 days
Percentile
27%
Versus all other CVEs
30-day change
Increase +0.15 pp
From 0.19% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Wordpress1 product
- wordpress-seo≤ 27.1.1 (fixed in 27.2)
Yoast1 product
2 vendors · 2 products