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.

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History

Wed, 02 Sep 2026 10:45:00 +0000

Type Values Removed Values Added
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.
Title Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directive Injection to RCE
Weaknesses CWE-74
References
Metrics cvssV3_1

{'score': 6.6, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: WPScan

Published:

Updated: 2026-09-02T14:57:38.690Z

Reserved: 2026-06-04T07:41:54.109Z

Link: CVE-2026-10821

cve-icon Vulnrichment

Updated: 2026-09-02T14:44:37.234Z

cve-icon NVD

Status : Received

Published: 2026-09-02T15:17:37.267

Modified: 2026-09-02T15:17:37.267

Link: CVE-2026-10821

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-03T12:00:04Z

Weaknesses