critical9.1
CVE-2026-42608
Grav has Unauthenticated Path Traversal & Arbitrary File Write in its FormFlash component
Impact
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
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | getgrav/grav | < 2.0.0-beta.2 | 2.0.0-beta.2 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Getgrav | Grav | before 2.0.0 Version 2.0.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-hmcx-ch82-3fv2
- https://github.com/getgrav/grav/security/advisories/GHSA-hmcx-ch82-3fv2
- https://github.com/getgrav/grav/commit/c66dfeb5ff679a1667678c6335eb9ff3255dfc47
- https://github.com/getgrav/grav/commit/d904efc33e03ebb597afde8d3368b28cf0423632
- https://nvd.nist.gov/vuln/detail/CVE-2026-42608