Security advisory

{
  "id": "48142766ffc6725069185ab91b4c8408fedc25d4b0a963859093cf200794d3f1",
  "url": "https://osv.dev/vulnerability/CVE-2020-15240",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-15240",
    "summary": "omniauth-auth0 (rubygems) versions >= 2.3.0 and < 2.4.1 improperly validate the JWT token signature when using the `jwt_validator.verify` method. Improper validation of the JWT token signature can allow an attacker to bypass authentication and authorization. You are affected by this vulnerability if all of the following conditions apply: 1. You are using `omniauth-auth0`. 2. You are using `JWTValidator.verify` method directly OR you are not authenticating using the SDK’s default Authorization Code Flow. The issue is patched in version 2.4.1.",
    "evidence": "osv:CVE-2020-15240",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2020-15240",
      "aliases": [
        "CVE-2020-15240",
        "GHSA-58r4-h6v8-jcvm"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/auth0/omniauth-auth0",
              "type": "GIT",
              "events": [
                {
                  "introduced": "c091def58305469b55365a29c12431b8cd07cd4a"
                },
                {
                  "fixed": "ce6824dd0ca306b5d0e7bf33fdae8404b0259da6"
                },
                {
                  "fixed": "fd3a14f4ccdfbc515d1121d6378ff88bf55a7a7a"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:auth0:omniauth-auth0:*:*:*:*:*:ruby:*:*",
                    "range": [
                      {
                        "introduced": "2.3.0"
                      },
                      {
                        "fixed": "2.4.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "fd3a14f4ccdfbc515d1121d6378ff88bf55a7a7a"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.4.0",
            "v2.3.1",
            "v2.3.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-15240.json"
          }
        }
      ],
      "modified": "2026-10-20T10:51:54.008553126Z",
      "provider": "osv",
      "references": [
        "https://github.com/auth0/omniauth-auth0/security/advisories/GHSA-58r4-h6v8-jcvm",
        "https://rubygems.org/gems/omniauth-auth0",
        "https://github.com/auth0/omniauth-auth0/commit/fd3a14f4ccdfbc515d1121d6378ff88bf55a7a7a"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-15240",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 383102,
  "published_at": "2020-10-21T18:15:12.813+00:00"
}