What is CVE-2025-66305?

CVE-2025-66305 is a medium-severity vulnerability in Getgrav Grav, classified under CWE-248. CVSS score: 4.9/10. Published 2025-12-01.

How severe is CVE-2025-66305?

Medium severity. CVSS v3 base score is 4.9 out of 10.

Vulnerability in Getgrav Grav

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.

EPSS: 0.003 (27.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.

Affected products

Getgrav Grav — versions 1.8.0, < 1.8.0-beta.27

Weakness classification (CWE)

CWE-248

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)

Frequently asked questions

What is CVE-2025-66305?: CVE-2025-66305 is a medium-severity vulnerability in Getgrav Grav, classified under CWE-248. CVSS score: 4.9/10. Published 2025-12-01.
How severe is CVE-2025-66305?: Medium severity. CVSS v3 base score is 4.9 out of 10.