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.
https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6
https://github.com/getgrav/grav/commit/ed640a13143c4177af013cf001969ed2c5e197ee
Published: 2025-12-01
Updated: 2025-12-03
Base Score: 6.1
Vector: CVSS2#AV:N/AC:L/Au:M/C:N/I:N/A:C
Severity: Medium
Base Score: 4.9
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00044