CVE-2026-42608 HIGH

CVE-2026-42608: Grav: Unauthenticated Path Traversal & Arbitrary File Write in FormFlash component.

Vendor Getgrav
Product grav
Weakness CWE-22 · Path traversal
Published May 11, 2026
Last update May 11, 2026

CVSS base score

8.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 11, 2026 CVE published
May 11, 2026 Record updated