GitHub Security Advisory: GHSA-3rh2-v3gr-35p9
Package: github.com/minio/minio (GO)
Severity: HIGH (CVSS 7.1)
CWE: CWE-287: Improper Authentication
Vulnerable versions: >= 0.0.0[PII_REDACTED]4456-468a9fae83e9, <= 0.0.0[PII_REDACTED]1848-7aac2a2c5b7c
Patched in: unpatched

Summary: MinIO is Vulnerable to SSE Metadata Injection via Replication Headers

Details:
## 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 Versions

All 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.2026-03-26T21-24-40Z

### 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_[PII_REDACTED]2440.0.0_amd64.deb](https://dl.min.io/aistor/minio/rel