CVE-2021-36788:
Cross-site Scripting in the yoast_seo TYPO3 extension
5.4
CVSS ScoreBasic Information
CVE ID
GHSA ID
EPSS Score
-
CWE
Published
9/1/2021
Updated
2/1/2023
KEV Status
No
Technology
PHP
PHPTechnical Details
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
| Package Name | Ecosystem | Vulnerable Versions | First Patched Version |
|---|---|---|---|
| yoast-seo-for-typo3/yoast_seo | composer | < 7.2.3 | 7.2.3 |
Vulnerability Intelligence
Miggo AI
Miggo AIRoot Cause Analysis
The patch explicitly adds sanitization (strip_tags() in PHP, stripFullTags() in JS) to these functions. The original code in PreviewService.php decoded HTML entities without removing tags, StructuredDataProviderManager.php allowed unsafe JSON slashes, and the JS actions lacked input sanitization. These un-sanitized outputs would render user-controlled data directly into HTML/script contexts, creating XSS opportunities.