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

2026-03-21 14:57

Osvaldo Noe Gonzalez Del Rio (Os)

Strategic Overview

Status

Patched in 27.2

Affected PluginYoast SEO – Advanced SEO with real-time guidance and built-in AI

Affected Version<= 27.1.1

CVSS6.4Medium

CVECVE-2026-3427

View all Yoast SEO – Advanced SEO with real-time guidance and built-in AI vulnerabilities

Vulnerability Overview

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.

Technical Analysis

REMEDIATION: Update to version 27.2, or a newer patched version --- IDENTIFIER: CWE-79 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

External References

https://www.cve.org/CVERecord?id=CVE-2026-3427 https://www.wordfence.com/threat-intel/vulnerabilities/id/fee1fef5-5716-49e0-a04e-d0dae527fcfc

CVSS Vector

6.4

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

This record contains material that is subject to copyright

CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

https://www.cve.org/Legal/TermsOfUse

Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.

https://www.wordfence.com/wordfence-intelligence-terms-and-conditions/