{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.30.0"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "d06ed1be13ef77e4f75ef06beb6ab829e2eef191"
            }
          ],
          "repo": "https://github.com/mozilla/geckodriver",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.",
  "id": "CVE-2021-4138",
  "modified": "2026-03-13T21:54:06.905590533Z",
  "published": "2022-05-02T23:15:08.057Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/mozilla/geckodriver/releases/tag/v0.30.0"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1652612"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}