{"id":"CVE-2026-42608","aliases":["GHSA-hmcx-ch82-3fv2"],"url":"https://o3.security/vulnerability/CVE-2026-42608","summary":"Grav: Unauthenticated Path Traversal & Arbitrary File Write in FormFlash component.","details":"Grav is a file-based Web platform. Prior to 2.0.0-beta.2, there is a Path Traversal vulnerability within the FormFlash core component. By manipulating the session_id (passed as __form-flash-id in POST requests), an unauthenticated attacker can traverse the filesystem to create arbitrary directories and write an index.yaml file containing attacker-controlled data. This vulnerability can lead to unauthorized modification of application behavior, potential data integrity issues, and service disruption in production environments. This vulnerability is fixed in 2.0.0-beta.2.","published":"2026-05-11T15:02:15.956Z","modified":"2026-08-07T11:51:06.283614036Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"getgrav/grav","fixedVersion":"2.0.0-beta.2"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42608.json"},{"type":"ADVISORY","url":"https://github.com/getgrav/grav/security/advisories/GHSA-hmcx-ch82-3fv2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42608"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:51:06.283614036Z"}}