Path traversal in Grav CMS - CVE-2026-42608
Published: May 5, 2026
Vulnerability identifier: #VU130086
CSH Severity: High
CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-42608
CWE-ID: CWE-22
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to write arbitrary files.
The vulnerability exists due to path traversal in FormFlash::__construct() / getTmpDir() when processing the __form-flash-id POST parameter. A remote attacker can send a specially crafted POST request with traversal sequences to write arbitrary files.
A vulnerable instance must expose at least one form-enabled page.
Affected software
Grav CMS
How to mitigate CVE-2026-42608
Install security update from vendor's website.
Grav CMS - update to 2.0.0 beta.2