CVE-2026-10821
Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directive Injection to RCE
- State
- Published
- Severity
- 6.6 Medium
- Published
- Sep 2, 2026
- Updated
- Sep 2, 2026
- Reserved
- Jun 4, 2026
Description
The Yoast SEO Premium WordPress plugin before 27.6.1 does not sanitize control characters from redirect origins before writing them to the site's Apache configuration file when the file-based redirect mode is enabled, and the redirect-creation endpoint is reachable by users with only Author-level access. This allows such users to inject arbitrary newline-delimited Apache directives into the root .htaccess file. On Apache servers that honour PHP directives, the injection can be chained with the user's own media upload (a polyglot image carrying a PHP payload) and an auto_prepend_file directive to achieve Remote Code Execution.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.6 Medium | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H | WPScan |
Weaknesses
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Affected Products
| Product | Versions |
|---|---|
Yoast SEO PremiumUnknown |
|
References
- https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/exploitvdb-entrytechnical-description
- https://yoast.com/yoast-seo-premium-may-26-2026/vendor-advisory
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