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Grav EUVDEUVD-2025-200107

| CVE-2025-66303 MEDIUM
Uncontrolled Resource Consumption (CWE-400)
2025-12-01 security-advisories@github.com GHSA-x62q-p736-3997
4.9
CVSS 3.1 · Vendor: github
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource consumption limits
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

Service disruption affecting availability. In critical infrastructure, DoS can have cascading effects on dependent systems. With a CVSS score of 4.9 (MEDIUM), this represents a moderate risk.

Exploit ScenarioDerived

An attacker sends specially crafted requests that cause excessive resource consumption (CPU, memory, disk) or trigger a crash in the target application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 15, 2026

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, A Denial of Service (DoS) vulnerability has been identified in Grav related to the handling of scheduled_at parameters. Specifically, the application fails to properly sanitize input for cron expressions. By manipulating the scheduled_at parameter with a malicious input, such as a single quote, the application admin panel becomes non-functional, causing significant disruptions to administrative operations. The only way to recover from this issue is to manually access the host server and modify the backup.yaml file to correct the corrupted cron expression. This vulnerability is fixed in 1.8.0-beta.27.

Earlier versions of this analysis (1)
v1 Mar 15, 2026 - 13:34 CVSS 4.9

RemediationAI

A vendor patch is available — apply it immediately. Implement rate limiting and input validation. Use timeout mechanisms for resource-intensive operations. Deploy DDoS protection where applicable.

Affected VersionsENISA

grav < 1.8.0-beta.27

Affected Packages

composer getgrav/grav fix: 1.8.0-beta.27
euvd grav fix: 1.8.0-beta.27

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in composer, euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

A denial of service vulnerability allows an attacker to disrupt the normal functioning of a system, making it unavailable to legitimate users. This vulnerability is classified as Uncontrolled Resource Consumption (CWE-400).

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (github) PRIMARY 4.9 MEDIUM
AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Primary rating from Vendor (github) · only source for this CVE.

CVSS VectorVendor: github

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

3
Patch released
Mar 15, 2026 - 13:34 nvd
Patch available
PoC Detected
Dec 03, 2025 - 16:03 vuln.today
Public exploit code
CVE Published
Dec 01, 2025 - 22:15 nvd
MEDIUM 4.9

Executive ViewAI

Why It Matters

Organizations using Grav should be aware of moderate risk from CVE-2025-66303, a resource exhaustion vulnerability rated CVSS 4.9. Service availability could be impacted. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: implement rate limiting and resource quotas.

Threat Intelligence Overview

EPSS Score
0.1%
Top 79% exploitable
Exploit
POC
Public exploit code exists
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
No
Human Impact
Low

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +24
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

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