ex_aws_sns SigningCertURL not validated in verify_message/1

{
  "id": "7680e94ddb6a2789ae94fa3f99ab6a378cbe5dce73af9c0889737cd7af1eccf9",
  "url": "https://osv.dev/vulnerability/CVE-2026-47074",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ex_aws_sns SigningCertURL not validated in verify_message/1",
    "summary": "Improper Certificate Validation vulnerability in ex-aws ex_aws_sns (ExAws.SNS, ExAws.SNS.PublicKeyCache modules) allows Signature Spoofing by Improper Validation. This vulnerability is associated with program files lib/ex_aws/sns.ex, lib/ex_aws/sns/public_key_cache.ex and program routines 'Elixir.ExAws.SNS':verify_message/1, 'Elixir.ExAws.SNS.PublicKeyCache':get/1. 'Elixir.ExAws.SNS':verify_message/1 fetches the signing certificate from the SigningCertURL field of the incoming SNS message without validating that the URL uses HTTPS or that the host matches an AWS-owned SNS certificate domain. An unauthenticated attacker who can POST to an endpoint that calls verify_message/1 can supply an attacker-controlled SigningCertURL, sign a forged SNS message with their own key, and cause the function to return :ok, completely bypassing SNS signature verification. This issue affects ex_aws_sns: from 2.0.1 before 2.3.5.",
    "evidence": "osv:CVE-2026-47074",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-47074",
      "aliases": [
        "CVE-2026-47074",
        "EEF-CVE-2026-47074",
        "GHSA-8jgf-23q5-x7xx"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ex-aws/ex_aws_sns",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a7ec21880943f4dac1d59bda557db0ffcd2b61fa"
                },
                {
                  "fixed": "1853d280b152d10384a1e21a22cf22152a60be48"
                },
                {
                  "introduced": "775d31ffb1e78702d78275ad8841be132d678b50"
                },
                {
                  "fixed": "97626db164a68b60c87f03fd3238551076b8a9ac"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "a7ec21880943f4dac1d59bda557db0ffcd2b61fa"
                      },
                      {
                        "fixed": "1853d280b152d10384a1e21a22cf22152a60be48"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "2.0.1"
                      },
                      {
                        "fixed": "2.3.5"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1853d280b152d10384a1e21a22cf22152a60be48"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.3.3",
            "v2.3.2",
            "v2.3.1",
            "v2.3.0",
            "v2.2.0",
            "v2.0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47074.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.751022787Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-47074.html",
        "https://github.com",
        "https://hex.pm",
        "https://osv.dev/vulnerability/EEF-CVE-2026-47074",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47074.json",
        "https://github.com/ex-aws/ex_aws_sns/security/advisories/GHSA-8jgf-23q5-x7xx",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-47074",
        "https://github.com/ex-aws/ex_aws_sns/commit/1853d280b152d10384a1e21a22cf22152a60be48",
        "https://github.com/ex-aws/ex_aws_sns"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-295"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47074.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-47074",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493380,
  "published_at": "2026-05-28T09:05:54.815+00:00"
}