CVE Tools
Sign in

CVE-2025-66305

Grav vulnerable to Denial of Service via Improper Input Handling in 'Supported' Parameter

Published: Dec 1, 2025Updated: Dec 3, 2025 Sources: CVE List NVD GHSACWE-248
NVD MITRE
4.9CVSSMEDIUM
EPSS Score
0.3%
Top 75.3%
CISA KEV
Not in KEV
Exploits
1 Known
Remediation
Patch Available

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 Vector Breakdown

AV:NAC:LPR:HUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:HPrivileges Required
High
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-248

Affected Products

gravgetgrav
On-premCMS Plugin
Web & CMS Plugins / cms-core
getgrav/gravPackagistOSS Libraries
getgravoss-projectWeb & CMS Pluginsaka grav, grav-plugin-admin, getgrav/grav
packagistpackage-ecosystemOSS Libraries

Exploitability

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available

References

https://github.com/getgrav/grav/commit/ed640a13143c4177af013cf001969ed2c5e197ee
github.com
https://github.com/getgrav/grav/security/advisories/GHSA-m8vh-v6r6-w7p6
github.com
https://nvd.nist.gov/vuln/detail/CVE-2025-66305
nvd.nist.gov
and 1 more references View all →

Timeline

Published
Dec 1, 2025
Last Updated
Dec 3, 2025

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2025-66305 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows