CVE-2026-10821

Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directive Injection to RCE

MEDIUM
6.6
CVSS Score
Published: September 2, 2026 at 02:16 PM UTC
Updated: September 3, 2026 at 06:04 PM UTC
1 product affected across 1 vendorYoast SEO Premium

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Severity
MEDIUM6.6
Exploit prediction
EPSS 0.7%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

60%
v < 27.6.1
Affected range stops below 27.6.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

ExploitVDB EntryTechnical Description
Source: cverecord
https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/
Vendor Advisory
Source: cverecord
https://yoast.com/yoast-seo-premium-may-26-2026/

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.6MEDIUMWPScan
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-74

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