CVE-2025-66305: Getgrav Grav

Medium severity, CVSS 4.9. EPSS: 0.4% chance of exploitation in the next 30 days.

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, a Denial of Service (DoS) vulnerability was identified in the "Languages" submenu of the Grav admin configuration panel (/admin/config/system). Specifically, the Supported parameter fails to properly validate user input. If a malformed value is inserted—such as a single forward slash (/) or an XSS test string—it causes a fatal regular expression parsing error on the server. This leads to application-wide failure due to the use of the preg_match() function with an improperly constructed regular expression, resulting in an error. Once triggered, the site becomes completely unavailable to all users. This vulnerability is fixed in 1.8.0-beta.27.

Affected products

• Getgrav Grav: from 1.7.48, before 1.8.0 (fixed in 1.8.0); version 1.8.0 only

Published 2025-12-01. Last modified 2026-06-17.