{"id":"CVE-2026-42845","summary":"Grav: Anonymous Page Content Overwrite via Form File Upload filename Override","details":"The form plugin for Grav adds the ability to create and use forms. Prior to 9.1.0 , there is an unauthenticated page-content overwrite via file upload (GHSA-w4rc-p66m-x6qq). Public form uploads now strip path components from the POST-supplied filename and hard-block page-content extensions (`md`, `yaml`, `yml`, `json`, `twig`, `ini`) regardless of the configurable dangerous-extensions list. A permissive `accept` policy combined with the default `destination: self@` could otherwise let an attacker overwrite the page's own `.md` and pivot to super-admin via a `process: save` action. This vulnerability is fixed in 9.1.0.","aliases":["GHSA-w4rc-p66m-x6qq"],"modified":"2026-07-08T08:12:35.242622226Z","published":"2026-05-11T15:44:35.524Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-73"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42845.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42845.json"},{"type":"ADVISORY","url":"https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42845"},{"type":"FIX","url":"https://github.com/getgrav/grav-plugin-form/commit/48bacc4187e1cff815000e526d5ca2878484867f"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/getgrav/grav-plugin-form","events":[{"introduced":"0"},{"fixed":"48bacc4187e1cff815000e526d5ca2878484867f"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"9.1.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["4.0.0","3.0.0-rc.4","3.0.0-rc.3","3.0.0-rc.2","3.0.0-rc.1","3.0.0-beta.5","3.0.0-beta.4","3.0.0-beta.3","3.0.0-beta.2","3.0.0-beta.1","2.8.0-rc.2","2.8.0-rc.1","2.0.8-rc.1","2.0.0-rc.1","1.3.0-rc.4","1.3.0-rc.3","1.3.0-rc.2","1.3.0-rc.1","1.3.0-beta.6","1.3.0-beta.4","1.3.0-beta.3","1.3.0-beta.2","1.3.0-beta.1","0.7.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42845.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P"}]}