CVE-2025-66305

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.

CVSS v3.1 Score

4.9

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-248 CWE-248

Affected Products

Vendor	Product	Versions
getgrav	grav	1.7.48 — 1.8.0
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All
getgrav	grav	All

References

Advisories & Patches

https://github.com/getgrav/grav/commit/ed640a13143c4177af013cf001969ed2c5e197ee https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6 https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6

Exploits

https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6 https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6

Frequently Asked Questions

What is CVE-2025-66305? +

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. It has a CVSS v3.1 base score of 4.9 (MEDIUM).

How severe is CVE-2025-66305? +

CVE-2025-66305 has a CVSS v3.1 score of 4.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-66305? +

CVE-2025-66305 affects products from getgrav, specifically: grav. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-66305? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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