{"id":"CVE-2026-42845","state":"PUBLISHED","title":"Grav: Anonymous Page Content Overwrite via Form File Upload filename Override","description":"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.","publishedAt":"2026-05-11T15:44:35.524Z","updatedAt":"2026-05-12T13:49:49.704Z","severity":{"score":7.7,"label":"High","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["getgrav grav-plugin-form"],"affected":[{"vendor":"getgrav","product":"grav-plugin-form","versions":[{"version":"< 9.1.0","status":"affected"}]}],"references":["https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq","https://github.com/getgrav/grav-plugin-form/commit/48bacc4187e1cff815000e526d5ca2878484867f"],"weaknesses":["CWE-73"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/42xxx/CVE-2026-42845.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42845","state":"PUBLISHED","datePublished":"2026-05-11T15:44:35.524Z","dateUpdated":"2026-05-12T13:49:49.704Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-30T16:44:48.377Z"},"containers":{"cna":{"title":"Grav: Anonymous Page Content Overwrite via Form File Upload filename Override","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"getgrav","product":"grav-plugin-form","versions":[{"version":"< 9.1.0","status":"affected"}]}],"references":[{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq","name":"https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/getgrav/grav-plugin-form/commit/48bacc4187e1cff815000e526d5ca2878484867f","name":"https://github.com/getgrav/grav-plugin-form/commit/48bacc4187e1cff815000e526d5ca2878484867f","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":7.7,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-73","lang":"en","description":"CWE-73: External Control of File Name or Path","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-11T15:44:35.524Z"},"source":{"advisory":"GHSA-w4rc-p66m-x6qq","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-12T13:49:13.568715Z","id":"CVE-2026-42845","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-12T13:49:49.704Z"}}]}}}