EUVD-2025-200105
GHSA-m8vh-v6r6-w7p6
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
5Tags
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.
Analysis
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.
Technical Context
Cross-site scripting (XSS) allows injection of client-side scripts into web pages viewed by other users due to insufficient output encoding.
Affected Products
Affected products: Getgrav Grav
Remediation
A vendor patch is available — apply it immediately. Encode all user-supplied output contextually (HTML, JS, URL). Implement Content Security Policy (CSP) headers. Use HTTPOnly and Secure cookie flags.
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External POC / Exploit Code
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