{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.1.1.0"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "ed39a503c84d9608d0f301f12ae128f36c4faf38"
            },
            {
              "fixed": "0675b25ae9cc10b5fdc8ea3a32c642979762d45e"
            }
          ],
          "repo": "https://github.com/ghostlander/halcyon",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "A vulnerability has been found in ghostlander Halcyon and classified as critical. Affected by this vulnerability is the function CBlock::AddToBlockIndex of the file src/main.cpp of the component Block Verification. The manipulation leads to improper access controls. The attack can be launched remotely. Upgrading to version 1.1.1.0-hal is able to address this issue. The identifier of the patch is 0675b25ae9cc10b5fdc8ea3a32c642979762d45e. It is recommended to upgrade the affected component. The identifier VDB-217417 was assigned to this vulnerability.",
  "id": "CVE-2021-4300",
  "modified": "2026-04-01T23:09:49.058825397Z",
  "published": "2023-01-04T22:15:08.903Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/ghostlander/Halcyon/releases/tag/v1.1.1.0-hal"
    },
    {
      "type": "REPORT",
      "url": "https://vuldb.com/?id.217417"
    },
    {
      "type": "REPORT",
      "url": "https://vuldb.com/?ctiid.217417"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ghostlander/Halcyon/commit/0675b25ae9cc10b5fdc8ea3a32c642979762d45e"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}