{"id":"CVE-2026-10821","state":"PUBLISHED","title":"Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directive Injection to RCE","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.","publishedAt":"2026-09-02T14:16:44.007Z","updatedAt":"2026-09-02T14:57:38.690Z","severity":{"score":6.6,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H","source":"WPScan"},"assigner":"WPScan","products":["Unknown Yoast SEO Premium"],"affected":[{"vendor":"Unknown","product":"Yoast SEO Premium","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"27.6.1","versionType":"semver"}]}],"references":["https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/","https://yoast.com/yoast-seo-premium-may-26-2026/"],"weaknesses":["CWE-74"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/10xxx/CVE-2026-10821.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-10821","state":"PUBLISHED","datePublished":"2026-09-02T14:16:44.007Z","dateUpdated":"2026-09-02T14:57:38.690Z","assignerShortName":"WPScan","assignerOrgId":"1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81","dateReserved":"2026-06-04T07:41:54.109Z"},"containers":{"cna":{"title":"Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directive Injection to RCE","descriptions":[{"lang":"en","value":"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":[{"vendor":"Unknown","product":"Yoast SEO Premium","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"27.6.1","versionType":"semver"}]}],"references":[{"url":"https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/","tags":["exploit","vdb-entry","technical-description"]},{"url":"https://yoast.com/yoast-seo-premium-may-26-2026/","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H","baseScore":6.6,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"description":"CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"WPScan","orgId":"1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81","dateUpdated":"2026-09-02T14:16:44.007Z"},"credits":[{"lang":"en","value":"Tin Pham (TF1T)","type":"finder"},{"lang":"en","value":"Trong Pham (dtro)","type":"finder"},{"lang":"en","value":"Hao Ngo","type":"finder"},{"lang":"en","value":"WPScan","type":"coordinator"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"WPScan CVE Generator"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-10821","role":"CISA Coordinator","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-09-02T14:48:28.117001Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-74","lang":"en","type":"CWE","description":"CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-02T14:57:38.690Z"}}]}}}