{"api_version":"1","generated_at":"2026-09-13T15:05:34+00:00","cve":"CVE-2026-10821","urls":{"html":"https://cve.report/CVE-2026-10821","api":"https://cve.report/api/cve/CVE-2026-10821.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-10821","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-10821"},"summary":{"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.","state":"PUBLISHED","assigner":"WPScan","published_at":"2026-09-02 15:17:37","updated_at":"2026-09-03 17:50:37"},"problem_types":["CWE-74","CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')","CWE-74 CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')"],"metrics":[{"version":"3.1","source":"contact@wpscan.com","type":"Secondary","score":"6.6","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"6.6","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":6.6,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://yoast.com/yoast-seo-premium-may-26-2026/","name":"https://yoast.com/yoast-seo-premium-may-26-2026/","refsource":"contact@wpscan.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/","name":"https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/","refsource":"contact@wpscan.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-10821","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-10821","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Unknown","product":"Yoast SEO Premium","version":"affected 27.6.1 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Tin Pham (TF1T)","lang":"en"},{"source":"CNA","value":"Trong Pham (dtro)","lang":"en"},{"source":"CNA","value":"Hao Ngo","lang":"en"},{"source":"CNA","value":"WPScan","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"10821","cve":"CVE-2026-10821","epss":"0.005120000","percentile":"0.418010000","score_date":"2026-09-07","updated_at":"2026-09-08 00:05:28"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-10821","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","timestamp":"2026-09-02T14:48:28.117001Z","version":"2.0.3"},"type":"ssvc"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-74","description":"CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-02T14:57:38.690Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"Yoast SEO Premium","vendor":"Unknown","versions":[{"lessThan":"27.6.1","status":"affected","version":"0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"Tin Pham (TF1T)"},{"lang":"en","type":"finder","value":"Trong Pham (dtro)"},{"lang":"en","type":"finder","value":"Hao Ngo"},{"lang":"en","type":"coordinator","value":"WPScan"}],"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."}],"metrics":[{"cvssV3_1":{"baseScore":6.6,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"description":"CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-02T14:16:44.007Z","orgId":"1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81","shortName":"WPScan"},"references":[{"tags":["exploit","vdb-entry","technical-description"],"url":"https://wpscan.com/vulnerability/2ddd8362-7248-48de-aab9-74c70e7d5dd6/"},{"tags":["vendor-advisory"],"url":"https://yoast.com/yoast-seo-premium-may-26-2026/"}],"source":{"discovery":"EXTERNAL"},"title":"Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directive Injection to RCE","x_generator":{"engine":"WPScan CVE Generator"}}},"cveMetadata":{"assignerOrgId":"1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81","assignerShortName":"WPScan","cveId":"CVE-2026-10821","datePublished":"2026-09-02T14:16:44.007Z","dateReserved":"2026-06-04T07:41:54.109Z","dateUpdated":"2026-09-02T14:57:38.690Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-02 15:17:37","lastModifiedDate":"2026-09-03 17:50:37","problem_types":["CWE-74","CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')","CWE-74 CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')"],"metrics":{"cvssMetricV31":[{"source":"contact@wpscan.com","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":0.7,"impactScore":5.9}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-09-02T14:48:28.117001Z","id":"CVE-2026-10821","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"10821","Ordinal":"1","Title":"Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directi","CVE":"CVE-2026-10821","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"10821","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Yoast SEO Premium < 27.6.1 - Author+ Arbitrary .htaccess Directi"}]}}}