CVE-2025-66305
moderate-risk
Published 2025-12-01
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.
Do I need to act?
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0.22% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.9/10
Medium
NETWORK
/ LOW complexity
Affected Products (20)
Affected Vendors
43
/ 100
moderate-risk
Severity
20/34 · Moderate
Exploitability
1/34 · Minimal
Exposure
22/34 · High