Summary
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 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
Proof of Concept
Change the value of
scheduled_atparameter to'as shown in the following figures at thehttp://127.0.0.1/admin/toolsendpoint, and observe the response in the second figure:
Figure: Http request on tool endpoint
Figure: Http response on tool endpointWhen 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.yamlfile, as shown in the second figure:
Figure: Error message view
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.
Impact
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
CVE-2025-66303 has a CVSS score of 4.9 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.8.0-beta.27); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2025-66303? CVE-2025-66303 is a medium-severity uncontrolled resource consumption vulnerability in getgrav/grav (composer), affecting versions < 1.8.0-beta.27. It is fixed in 1.8.0-beta.27. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- How severe is CVE-2025-66303? CVE-2025-66303 has a CVSS score of 4.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of getgrav/grav are affected by CVE-2025-66303? getgrav/grav (composer) versions < 1.8.0-beta.27 is affected.
- Is there a fix for CVE-2025-66303? Yes. CVE-2025-66303 is fixed in 1.8.0-beta.27. Upgrade to this version or later.
- Is CVE-2025-66303 exploitable, and should I be worried? Whether CVE-2025-66303 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-66303 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-66303? Upgrade
getgrav/gravto 1.8.0-beta.27 or later.