---
id: CVE-2025-66303
title: Grav is a file-based Web platform
summary: >-
  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 i…
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
vendor: getgrav
product: grav
affected:
  - grav < 1.8.0
  - grav = 1.8.0
patched:
  - grav 1.8.0
published: '2025-12-01'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T00:10:00.127'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-66303'
references:
  - url: >-
      https://github.com/getgrav/grav/commit/9d11094e4133f059688fad1e00dbe96fb6e3ead7
    label: security-advisories@github.com
  - url: 'https://github.com/getgrav/grav/security/advisories/GHSA-x62q-p736-3997'
    label: security-advisories@github.com
  - url: 'https://github.com/getgrav/grav/security/advisories/GHSA-x62q-p736-3997'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00387
epssPercentile: 0.30061
ingestedAt: '2026-09-26T00:22:39.992Z'
---

## Overview

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.

## Affected

- `grav < 1.8.0`
- `grav = 1.8.0`

## Remediation

Upgrade past the affected range:

- `grav 1.8.0`