{"id":"CVE-2026-42845","aliases":["GHSA-w4rc-p66m-x6qq"],"url":"https://o3.security/vulnerability/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.","published":"2026-05-11T15:44:35.524Z","modified":"2026-08-07T11:50:19.072251022Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"getgrav/grav-plugin-form","fixedVersion":"9.1.0"}],"fix":{"url":"https://github.com/getgrav/grav-plugin-form/commit/48bacc4187e1cff815000e526d5ca2878484867f","label":"getgrav/grav-plugin-form@48bacc4"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:19.072251022Z"}}