MinIO vulnerable to Path Traversal via msgpack Body in `ReadMultiple` Storage-REST Endpoint

{
  "id": "6aac18ae94fc18cf458b76dfe42088d4b49fd0a898c67d9dce31d647666f5242",
  "url": "https://osv.dev/vulnerability/GHSA-xh8f-g2qw-gcm7",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MinIO vulnerable to Path Traversal via msgpack Body in `ReadMultiple` Storage-REST Endpoint",
    "summary": "### Impact _What kind of vulnerability is it? Who is impacted?_ A path traversal vulnerability in MinIO's `ReadMultiple` internode storage-REST endpoint allows a caller holding the cluster root JWT to read files from outside the configured drive roots, bounded only by the MinIO process UID. Distributed-erasure (multi-node) MinIO deployments are impacted. Single-node standalone deployments do not register the route and are not affected. The attack requires an HS512 JWT signed with `MINIO_ROOT_PASSWORD` and carrying `accessKey = MINIO_ROOT_USER` — the same secret every peer in the cluster holds to authenticate internode traffic, so a compromised peer or any actor in possession of the root credential can mint one. The `ReadMultiple` handler (`cmd/storage-rest-server.go`) decodes a msgpack `ReadMultipleReq` body containing `Bucket`, `Prefix`, and `Files` fields and forwards them to `xlStorage.ReadMultiple` (`cmd/xl-storage.go`) without validation: ```go volumeDir := pathJoin(s.drivePath, req.Bucket) // traversal resolves here for _, f := range req.Files { fullPath := pathJoin(volumeDir, req.Prefix, f) data, mt, err = s.readAllDataWithDMTime(ctx, req.Bucket, volumeDir, fullPath) } ``` `pathJoin` calls `path.Clean`, which resolves `..` components and produces an absolute path anywhere on the filesystem — it is not a root jail. The global `setRequestValidityMiddleware` rejects `..` in `r.URL.Path` and `r.Form` but does not inspect request bodies, so msgpack-encoded traversal bypasse",
    "evidence": "osv:GHSA-xh8f-g2qw-gcm7",
    "products": [
      {
        "name": {
          "value": "github.com/minio/minio",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.0.0-20260414213245",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "GHSA-xh8f-g2qw-gcm7",
      "aliases": [
        "CVE-2026-42600",
        "GHSA-xh8f-g2qw-gcm7",
        "GO-2026-5757"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N"
        },
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.0.0-20220724015452"
                },
                {
                  "fixed": "0.0.0-20260414213245"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/minio/minio",
            "purl": "pkg:golang/github.com/minio/minio",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-xh8f-g2qw-gcm7/GHSA-xh8f-g2qw-gcm7.json"
          }
        }
      ],
      "modified": "2026-10-08T08:11:01.361068892Z",
      "provider": "osv",
      "references": [
        "https://github.com/minio/minio/security/advisories/GHSA-xh8f-g2qw-gcm7",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42600",
        "https://github.com/minio/minio"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "severity": "MODERATE",
        "github_reviewed": true,
        "nvd_published_at": "2026-05-11T22:22:11Z",
        "github_reviewed_at": "2026-05-05T20:05:05Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-42600",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/1/score"
  },
  "source_id": "core-osv",
  "document_id": 98748,
  "published_at": "2026-05-05T20:05:05+00:00"
}