CVE-2025-66303: Grav is vulnerable to a DOS on the admin panel

DOS on the admin panel Severity Rating: Medium

Vector: Denial Of Service

CVE: XXX

CWE: 400 - Uncontrolled Resource Consumption

CVSS Score: 4.9

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Analysis

A Denial of Service (DoS) vulnerability has been identified in the application related to the handling of scheduledat parameters. Specifically, the application fails to properly sanitize input for cron expressions. By manipulating the scheduledat 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

Proof of Concept

1) Change the value of scheduledat parameter to ' as shown in the following figures at the http://127.0.0.1/admin/tools endpoint, and observe the response in the second figure: !gravdos2 Figure: Http request on tool endpoint !gravdos3 Figure: Http response on tool endpoint

2) When trying to access the admin panel, the panel is broken as shown in the following figure. Additionally, the value change is reflected in the backup.yaml file, as shown in the second figure: !gravdos4 Figure: Error message view !gravdos5 Figure: Backup.yaml file

Workarounds No workaround is currently known

Timeline 2024-07-24 Issue identified

2024-09-27 Vendor contacted

About X41 D-Sec GmbH X41 is an expert provider for application security services. Having extensive industry experience and expertise in the area of information security, a strong core security team of world class security experts enables X41 to perform premium security services.

Fields of expertise in the area of application security are security centered code reviews, binary reverse engineering and vulnerability discovery. Custom research and IT security consulting and support services are core competencies of X41.