GHSA-xh8f-g2qw-gcm7: MinIO vulnerable to Path Traversal via msgpack Body in `ReadMultiple` Storage-REST Endpoint
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:`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 bypasses it.
Sibling storage methods (`StatInfoFile`, `ReadFileHandler`, `ReadVersion`)
validate their volume argument through `s.getVolDir(volume)`, which rejects
`..`; `ReadMultiple` skips this call.The attacker sends `POST /minio/storage/{drivePath}/v63/rmpl` with a
msgpack-encoded body carrying `../` sequences in the `Bucket` field. The
server opens the resulting path via `os.OpenFile` with `O_RDONLY|O_NOATIME`
and returns its contents in the msgpack response stream.**Impact by deployment:****Bare-metal with `User=minio` in the systemd unit** — the `O_NOATIME`
ownership check bounds the read to files owned by the MinIO UID. Reachable
secrets include TLS private keys, KMS/KES key material, systemd credentials,
and data belonging to other tenants sharing the same UID on the host.
Secrets leaked this way persist across cluster credential rotation.**Containerized running as UID 0** (the historical default for the official
Docker image, `docker-compose` examples, and Helm charts without
`securityContext.runAsNonRoot`) — the primitive escalates to arbitrary
host-filesystem disclosure: `/etc/shadow`, `/root/**`, Kubernetes
service-account tokens, cloud-init metadata caches.**Affected components:** `cmd/storage-rest-server.go` (`ReadMultiple` handler),
`cmd/xl-storage.go` (`xlStorage.ReadMultiple`).**CWE:** CWE-22 (Improper Limitation of a Pathname to a Restricted Directory
— 'Path Traversal')**CVSS v4.0 Score:** 6.9 (Medium)**Vector:** `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 VersionsAll MinIO releases from `RELEASE.2022-07-24T01-54-52Z` through the final
release of the minio/minio open-source project, `RELEASE.2025-09-07T16-13-09Z`.The vulnerability was introduced in commit
[`f939d1c18`](https://github.com/minio/minio/commit/f939d1c1831c71f4b1c14df6d9cd62b12ccce7a3)
("Independent Multipart Uploads",
[PR #15346](https://github.com/minio/minio/pull/15346)), which added the
`ReadMultiple` storage-REST endpoint as part of the multipart upload
redesign. The first affected release is `RELEASE.2022-07-24T01-54-52Z`.Patches**Fixed in**: MinIO AIStor `RELEASE.2026-04-14T21-32-45Z` (recommended
upgrade target). The fix — which removed the `ReadMultiple` handler, the
corresponding storage-driver method, the msgpack datatypes, the REST-client
wrapper, and the route registration — first shipped in **MinIO AIStor
`RELEASE.2024-10-23T19-38-07Z`**. Every AIStor release from
`RELEASE.2024-10-23T19-38-07Z` onward is unaffected; users should upgrade to
`RELEASE.2026-04-14T21-32-45Z` or later to pick up the accumulated fixes and
improvements shipped since.Binary Downloads| Platform | Architecture | Download                                                                    |
| -------- | ------------ | --------------------------------------------------------------------------- |
| Linux    | amd64        | [minio](https://dl.min.io/aistor/minio/release/linux-amd64/minio)           |
| Linux    | arm64        | [minio](https://dl.min.io/aistor/minio/release/linux-arm64/minio)           |
| macOS    | arm64        | [minio](https://dl.min.io/aistor/minio/release/darwin-arm64/minio)          |
| macOS    | amd64        | [minio](https://dl.min.io/aistor/minio/release/darwin-amd64/minio)          |
| Windows  | amd64        | [minio.exe](https://dl.min.io/aistor/minio/release/windows-amd64/minio.exe) |FIPS Binaries| Platform | Architecture | Download                                                                    |
| -------- | ------------ | --------------------------------------------------------------------------- |
| Linux    | amd64        | [minio.fips](https://dl.min.io/aistor/minio/release/linux-amd64/minio.fips) |
| Linux    | arm64        | [minio.fips](https://dl.min.io/aistor/minio/release/linux-arm64/minio.fips) |Package Downloads| Format | Architecture | Download                                                                                                                            |
| ------ | ------------ | ----------------------------------------------------------------------------------------------------------------------------------- |
| DEB    | amd64        | [minio_20260414213245.0.0_amd64.deb](https://dl.min.io/aistor/minio/release/linux-amd64/minio_20260414213245.0.0_amd64.deb)         |
| DEB    | arm64        | [minio_20260414213245.0.0_arm64.deb](https://dl.min.io/aistor/minio/release/linux-arm64/minio_20260414213245.0.0_arm64.deb)         |
| RPM    | amd64        | [minio-20260414213245.0.0-1.x86_64.rpm](https://dl.min.io/aistor/minio/release/linux-amd64/minio-20260414213245.0.0-1.x86_64.rpm)   |
| RPM    | arm64        | [minio-20260414213245.0.0-1.aarch64.rpm](https://dl.min.io/aistor/minio/release/linux-arm64/minio-20260414213245.0.0-1.aarch64.rpm) |Container ImagesHomebrew (macOS)Workarounds[Users of the open-source `minio/minio` project should upgrade to MinIO AIStor `RELEASE.2026-04-14T21-32-45Z` or later.](https://docs.min.io/enterprise/aistor-object-store/upgrade-aistor-server/community-edition/)If upgrading is not immediately possible:**Rotate the root credential and restrict who holds it.** The exploit
requires a JWT signed with `MINIO_ROOT_PASSWORD`. Treat the root credential
as the host-filesystem disclosure primitive that it is: rotate it after any
suspected exposure, store it only in the secret manager that bootstraps the
cluster, and do not hand it to applications or operators who only need
object-level access.**Do not run the MinIO container as UID 0.** Set
`securityContext.runAsNonRoot: true` (and a non-zero `runAsUser`) in
Kubernetes manifests, or add `--user` to `docker run`. This reduces the
blast radius from arbitrary host-filesystem disclosure to MinIO-UID-owned
files only.**Restrict the internode storage-REST port at the network layer.** In
distributed deployments, the storage-REST route is served on the same port
as the S3 API by default. Where feasible, use `--internode-port` to expose
internode traffic on a separate interface reachable only from other cluster
peers, and block that interface from client networks.Credits**Finders:** Discovered by Claude, Anthropic's AI assistant, and triaged by
**Adrian Denkiewicz** at **Doyensec** in collaboration with **Anthropic
Research**.ResourcesIntroducing commit: [`f939d1c18`](https://github.com/minio/minio/commit/f939d1c1831c71f4b1c14df6d9cd62b12ccce7a3)
([PR #15346](https://github.com/minio/minio/pull/15346))[CWE-22 — Improper Limitation of a Pathname to a Restricted Directory](https://cwe.mitre.org/data/definitions/22.html)[CVE-2022-35919 — MinIO admin-authenticated path traversal in server-update endpoint (same class, different channel)](https://github.com/minio/minio/security/advisories/GHSA-gr9v-6pcm-rqvg)[MinIO AIStor](https://min.io/aistor)
CVSS v4.0: 6.9
CVSS v3.1: 4.9