CVE-2025-66305

4.9 MEDIUM
Published: December 01, 2025 Modified: December 03, 2025

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6
Source: security-advisories@github.com
Exploit Vendor Advisory
https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
4.9 / 10.0
EPSS (Exploit Probability)
0.1%
19th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

getgrav