CVE-2025-66305

6.9 MEDIUM 0.4% exploit odds Fix listed Denial of service Web app

What it is

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.

At a glance

Exploitability: Can be exploited over the network with an admin-level account. High risk of service disruption.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-12-01 22:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 09:56 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 6.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-12-01 22:15 UTC
Last modified: 2026-06-17 09:56 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-248
Record status: Analyzed

Affected

Getgrav Grav < 1.8.0
Getgrav Grav 1.8.0

Attack profile CVSS 4.0 · 6.9

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: High
User interaction: None
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-66305.md and follow it. Check whether this project is affected by CVE-2025-66305. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record