GHSA-3rh2-v3gr-35p9: MinIO is Vulnerable to SSE Metadata Injection via Replication Headers
Impact_What kind of vulnerability is it? Who is impacted?_A flaw in `extractMetadataFromMime()` allows any authenticated user with `s3:PutObject` permission to inject internal server-side encryption metadata into objects by sending crafted `X-Minio-Replication-*` headers on a normal PutObject request. The server unconditionally maps these headers to `X-Minio-Internal-*` encryption metadata without verifying that the request is a legitimate replication request. Objects written this way carry bogus encryption keys and become **permanently unreadable** through the S3 API.Any authenticated user or service with `s3:PutObject` permission on any bucket can make objects permanently unreadable by injecting fake SSE encryption metadata. The attacker sends a standard PutObject request with `X-Minio-Replication-Server-Side-Encryption-*` headers but **without** the `X-Minio-Source-Replication-Request` header that marks legitimate replication traffic. The server maps these headers to internal encryption metadata (`X-Minio-Internal-Server-Side-Encryption-Sealed-Key`, etc.), causing all subsequent GetObject and HeadObject calls to treat the object as encrypted with keys that do not exist.This is a targeted denial-of-service vulnerability. An attacker can selectively corrupt individual objects or entire buckets. The `ReplicateObjectAction` IAM permission is never checked because the request is a normal PutObject, not a replication request.**Affected component:** `cmd/handler-utils.go`, function `extractMetadataFromMime()`.Affected VersionsAll MinIO releases through the final release of the minio/minio open-source project.The vulnerability was introduced in commit `468a9fae83e965ecefa1c1fdc2fc57b84ece95b0` ("Enable replication of SSE-C objects", [PR #19107](https://github.com/minio/minio/pull/19107), 2024-03-28). The first affected release is `RELEASE.2024-03-30T09-41-56Z`.Patches**Fixed in**: MinIO AIStor RELEASE.2026-03-26T21-24-40ZBinary 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_20260326212440.0.0_amd64.deb](https://dl.min.io/aistor/minio/release/linux-amd64/minio_20260326212440.0.0_amd64.deb) |
| DEB | arm64 | [minio_20260326212440.0.0_arm64.deb](https://dl.min.io/aistor/minio/release/linux-arm64/minio_20260326212440.0.0_arm64.deb) |
| RPM | amd64 | [minio-20260326212440.0.0-1.x86_64.rpm](https://dl.min.io/aistor/minio/release/linux-amd64/minio-20260326212440.0.0-1.x86_64.rpm) |
| RPM | arm64 | [minio-20260326212440.0.0-1.aarch64.rpm](https://dl.min.io/aistor/minio/release/linux-arm64/minio-20260326212440.0.0-1.aarch64.rpm) |Container ImagesHomebrew (macOS)Workarounds[Users of the open-source `minio/minio` project should upgrade to MinIO AIStor `RELEASE.2026-03-26T21-24-40Z` or later.](https://docs.min.io/enterprise/aistor-object-store/upgrade-aistor-server/community-edition/)If upgrading is not immediately possible:**Restrict replication headers at a reverse proxy / load balancer.** Drop or reject any request containing `X-Minio-Replication-Server-Side-Encryption-*` headers that does not also carry `X-Minio-Source-Replication-Request`. This blocks the injection path without modifying the server.**Audit IAM policies.** Limit `s3:PutObject` grants to trusted principals. While this reduces the attack surface, it does not eliminate the vulnerability since any authorized user can exploit it.ReferencesIntroducing commit: [`468a9fae8`](https://github.com/minio/minio/commit/468a9fae83e965ecefa1c1fdc2fc57b84ece95b0) ([PR #19107](https://github.com/minio/minio/pull/19107))[MinIO AIStor](https://min.io/aistor)
CVSS v4.0: 7.1
CVSS v3.1: 7.1