Yoast SEO Premium Plugin up to 27.6.0 on WordPress Redirect Creation Endpoint .htaccess injection

Summaryinfo

A vulnerability was found in Yoast SEO Premium Plugin up to 27.6.0. It has been rated as critical. Impacted is an unknown function of the file .htaccess of the component Redirect Creation Endpoint. Performing a manipulation results in injection. This vulnerability is cataloged as CVE-2026-10821. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Yoast SEO Premium Plugin up to 27.6.0. It has been classified as critical. This affects an unknown function of the file .htaccess of the component Redirect Creation Endpoint. The manipulation with an unknown input leads to a injection vulnerability. CWE is classifying the issue as CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at wpscan.com. This vulnerability is uniquely identified as CVE-2026-10821 since 06/04/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1055 according to MITRE ATT&CK.

Upgrading to version 27.6.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-70033). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• Yoast

Name

• SEO Premium Plugin

Version

• 27.0
• 27.1
• 27.2
• 27.3
• 27.4
• 27.5
• 27.6.0

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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