Cloud Metadata SSRF Protection Bypass via IPv6 Resolution

{
  "id": "9e31055e9fd028debd1a78c532c585f9806b4e894711dab4ece1bbae4668ad43",
  "url": "https://osv.dev/vulnerability/CVE-2026-27129",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Cloud Metadata SSRF Protection Bypass via IPv6 Resolution",
    "summary": "Craft is a content management system (CMS). In versions 4.5.0-RC1 through 4.16.18 and 5.0.0-RC1 through 5.8.22, the SSRF validation in Craft CMS’s GraphQL Asset mutation uses `gethostbyname()`, which only resolves IPv4 addresses. When a hostname has only AAAA (IPv6) records, the function returns the hostname string itself, causing the blocklist comparison to always fail and completely bypassing SSRF protection. This is a bypass of the security fix for CVE-2025-68437. Exploitation requires GraphQL schema permissions for editing assets in the `` volume and creating assets in the `` volume. These permissions may be granted to authenticated users with appropriate GraphQL schema access and/or Public Schema (if misconfigured with write permissions). Versions 4.16.19 and 5.8.23 patch the issue.",
    "evidence": "osv:CVE-2026-27129",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-27129",
      "aliases": [
        "CVE-2026-27129",
        "GHSA-v2gc-rm6g-wrw9"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/craftcms/cms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "c6671af5af9e45f57ca9ab50d4b30b07282819d3"
                },
                {
                  "fixed": "1a8db788c8b3de85c3aed09ac34046e230079481"
                },
                {
                  "introduced": "856f45f2766b1a1df5db437b5cd3fe5cce896b5b"
                },
                {
                  "fixed": "daf0ed01c7d2c194ba4a405290e43934d020eef2"
                },
                {
                  "introduced": "f6a8fb685d44e387435825e3a96809eeda4973a6"
                },
                {
                  "fixed": "2825388b4f32fb1c9bd709027a1a1fd192d709a3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.5.0"
                      },
                      {
                        "fixed": "4.16.19"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "5.0.1"
                      },
                      {
                        "fixed": "5.8.23"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:craftcms:craft_cms:5.0.0:-:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "5.0.0-NA"
                      },
                      {
                        "last_affected": "5.0.0-NA"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:craftcms:craft_cms:5.0.0:rc1:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "5.0.0-rc1"
                      },
                      {
                        "last_affected": "5.0.0-rc1"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "2825388b4f32fb1c9bd709027a1a1fd192d709a3"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "5.0.0-NA",
            "5.0.0-rc1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27129.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.096978601Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27129.json",
        "https://github.com/craftcms/cms/security/advisories/GHSA-v2gc-rm6g-wrw9",
        "https://github.com/craftcms/cms/security/advisories/GHSA-x27p-wfqw-hfcc",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-27129",
        "https://github.com/craftcms/cms/commit/2825388b4f32fb1c9bd709027a1a1fd192d709a3"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-918"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27129.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27129",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499215,
  "published_at": "2026-02-24T02:45:45.494+00:00"
}