{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "8.1"
                  },
                  {
                    "fixed": "8.1.4.1"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "8.0.5.2"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "2fc8838300133931e19eed3ea6cee76a7e83f19c"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "range": [
                  {
                    "fixed": "8ba746e0a786458c281060823f2ccc5c5f6312ac"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "v8.0.5.2",
                "range": [
                  {
                    "fixed": "235c597b100321b6bd2d62f8df63707f42b25b2d"
                  }
                ],
                "source": "REFERENCES_TAG"
              },
              {
                "original_tag": "v8.1.4.1",
                "range": [
                  {
                    "fixed": "3f290b759c8e2ffe7c257951b1255740751355e4"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "1cdd190a25e483b65f1f25bbd0f13a25d696b461"
            },
            {
              "fixed": "3f290b759c8e2ffe7c257951b1255740751355e4"
            },
            {
              "introduced": "0"
            },
            {
              "fixed": "235c597b100321b6bd2d62f8df63707f42b25b2d"
            },
            {
              "fixed": "2fc8838300133931e19eed3ea6cee76a7e83f19c"
            },
            {
              "fixed": "8ba746e0a786458c281060823f2ccc5c5f6312ac"
            }
          ],
          "repo": "https://github.com/rails/rails",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-wm3x-v3qw-4jh3"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-915"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126081.json"
  },
  "details": "Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, ActionController::Parameters#each_key delegates to the internal ActiveSupport::HashWithIndifferentAccess that holds the request parameters, so when called with a block it returns that hash instead of the Parameters instance. The hash does not respond to permitted?, so Active Model mass assignment (new, assign_attributes, update) accepts it without raising ActiveModel::ForbiddenAttributesError. An application that passes the return value of each_key to mass assignment could allow a remote, unauthenticated attacker to set attributes that the application does not permit, such as an authorization flag. This is an incomplete fix of CVE-2020-8164, which made each, each_pair and each_value return the Parameters instance but left each_key delegated. An application is affected if it passes the return value of ActionController::Parameters#each_key, called with a block, to mass assignment. Rails itself makes no such call. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.",
  "id": "CVE-2026-126081",
  "modified": "2026-11-12T02:30:35.242752414Z",
  "published": "2026-11-10T21:06:31.425Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/releases/tag/v8.0.5.2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/releases/tag/v8.1.4.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126081.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/rails/rails/security/advisories/GHSA-wm3x-v3qw-4jh3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126081"
    },
    {
      "type": "FIX",
      "url": "https://github.com/rails/rails/commit/2fc8838300133931e19eed3ea6cee76a7e83f19c"
    },
    {
      "type": "FIX",
      "url": "https://github.com/rails/rails/commit/8ba746e0a786458c281060823f2ccc5c5f6312ac"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Action Pack: Possible Strong Parameters bypass in Parameters#each_key"
}