CVE-2026-42608: Getgrav Grav

Critical severity, CVSS 9.1. EPSS: 0.5% chance of exploitation in the next 30 days.

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 products

• Getgrav Grav: before 2.0.0 (fixed in 2.0.0); version 2.0.0 only

Published 2026-05-11. Last modified 2026-06-17.