Path Traversal in Getgrav Grav
CVE-2026-42608
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (43.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Getgrav Grav — versions < 2.0.0-beta.2, 2.0.0
Weakness classification (CWE)
References
- github.com/getgrav/grav/security/advisories/GHSA-hmcx-ch82-3fv2 (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-42608?
- CVE-2026-42608 is a critical-severity vulnerability in Getgrav Grav, classified under Path Traversal. CVSS score: 9.1/10. Published 2026-05-11.
- How severe is CVE-2026-42608?
- Critical severity. CVSS v3 base score is 9.1 out of 10.