CVE-2025-66303: Getgrav/grav Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-x62q-p736-3997",
  "modified" : "2025-12-02T00:36:59Z",
  "published" : "2025-12-02T00:36:59Z",
  "aliases" : [ "CVE-2025-66303" ],
  "summary" : "Grav is vulnerable to a DOS on the admin panel",
  "details" : "# DOS on the admin panel\n**Severity Rating:** Medium \n\n**Vector:** Denial Of Service\n\n**CVE:** XXX\n\n**CWE:** 400 - Uncontrolled Resource Consumption\n\n**CVSS Score:** 4.9\n\n**CVSS Vector:** CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H\n\n## Analysis\n\nA 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.\n\nThe 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\n\n## Proof of Concept\n\n1) Change the value of `scheduled_at` 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:\n  ![gravdos2](https://github.com/user-attachments/assets/b2d8935f-c8ba-4eda-998a-8a20b3d5ef7c)\n  *Figure: Http request on tool endpoint*\n![gravdos3](https://github.com/user-attachments/assets/2a283254-316a-45b3-a5ac-6804e2494cd7)\n  *Figure: Http response on tool endpoint*\n\n2) 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:\n  ![gravdos4](https://github.com/user-attachments/assets/1257adcb-96c4-4b30-864e-9aa01e410ded)\n  *Figure: Error message view*\n![gravdos5](https://github.com/user-attachments/assets/4cef7c49-6a1e-4414-8332-3195aa2dfc77)\n  *Figure: Backup.yaml file*\n\n\n## Workarounds\nNo workaround is currently known\n\n# Timeline\n**2024-07-24** Issue identified\n\n**2024-09-27** Vendor contacted\n\n\n# About X41 D-Sec GmbH\nX41 is an expert provider for application security services.\nHaving extensive industry experience and expertise in the area of information\nsecurity, a strong core security team of world class security experts enables\nX41 to perform premium security services.\n\nFields of expertise in the area of application security are security centered\ncode reviews, binary reverse engineering and vulnerability discovery.\nCustom research and IT security consulting and support services are core\ncompetencies of X41.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "getgrav/grav"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.8.0-beta.27"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/getgrav/grav/security/advisories/GHSA-x62q-p736-3997"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-66303"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/getgrav/grav/commit/9d11094e4133f059688fad1e00dbe96fb6e3ead7"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/getgrav/grav"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-02T00:36:59Z",
    "nvd_published_at" : "2025-12-01T22:15:49Z"
  }
}