CVE-2026-42608CWE-22

Grav: Unauthenticated Path Traversal & Arbitrary File Write in FormFlash component.

High · published May 11, 2026

CVSS v4.0
8.8
EPSS
1%
Percentile
43.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.8 · HIGH
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
EPSS
0.00521 · 43.4th percentile
Weakness
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Published
2026-05-11T15:02Z
EPSS history
Timeline
  • 11 MAY 15:02Z
    Grav: Unauthenticated Path Traversal & Arbitrary File Write in FormFlash component.
    cvelistv5