CVE-2026-42608
Grav has Unauthenticated Path Traversal & Arbitrary File Write in its FormFlash component
Severity by source
Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by GHSA (high).
Description
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.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| composer::GitHub Security Advisory Composer | getgrav/grav | 2.0.0-beta.2 |
References
- https://github.com/getgrav/grav
- https://github.com/getgrav/grav/commit/c66dfeb5ff679a1667678c6335eb9ff3255dfc47
- https://github.com/getgrav/grav/commit/d904efc33e03ebb597afde8d3368b28cf0423632
- https://github.com/getgrav/grav/security/advisories/GHSA-hmcx-ch82-3fv2
- https://nvd.nist.gov/vuln/detail/CVE-2026-42608