# CVE-2026-34204: MinIO is Vulnerable to SSE Metadata Injection via Replication Headers

> Authenticated users can inject server-side encryption metadata via replication headers, bypassing intended security controls in MinIO object storage.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** GHSA-3rh2-v3gr-35p9, GO-2026-4896, MINI-8666-286m-47gj, MINI-c6p4-3gv7-fg4h

## What is CVE-2026-34204?

CVE-2026-34204 is a high-severity missing authorization vulnerability in minio, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

MinIO is a high-performance object storage system. Prior to version RELEASE.2026-03-26T21-24-40Z, 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. This issue has been patched in version RELEASE.2026-03-26T21-24-40Z.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-34204?

3 open source packages ship an affected version, including github.com/minio/minio. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/minio/minio` | Go | From 0.0.0-20240328174456-468a9fae83e9 | None |
| `github.com/minio/minio` | Go | From 0.0.0-20240328174456-468a9fae83e9 to 0.0.0-20260212201848-7aac2a2c5b7c | None |
| `github.com/minio/minio` | Go | From 0.0.0-20240328174456-468a9fae83e9 to 0.0.0-20260212201848-7aac2a2c5b7c | None |

Products: Minio Minio.

## How do I fix CVE-2026-34204?

Upgrade to a fixed version.

## Is CVE-2026-34204 being exploited?

There is no known exploitation of CVE-2026-34204 in the wild and no public exploit code.

## Other vulnerabilities in minio

- [CVE-2023-28434](https://insights.sbomify.com/CVE-2023-28434/): MinIO Security Feature Bypass (high 8.8, exploited in the wild)
- [CVE-2023-28432](https://insights.sbomify.com/CVE-2023-28432/): MinIO Information Disclosure (high 7.5, exploited in the wild)
- [CVE-2020-11012](https://insights.sbomify.com/CVE-2020-11012/): Authentication bypass MinIO Admin API (critical 9.3)
- [CVE-2026-33322](https://insights.sbomify.com/CVE-2026-33322/): MinIO: JWT Algorithm Confusion in OIDC Authentication (critical 9.2)
- [CVE-2026-33419](https://insights.sbomify.com/CVE-2026-33419/): MinIO: LDAP login brute-force via user enumeration and missing rate limit (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34204 and fix it if it is affected.

What it is: CVE-2026-34204 is a high-severity missing authorization vulnerability in minio, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34204 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/minio/minio (Go): affected from 0.0.0-20240328174456-468a9fae83e9; no fix listed
- github.com/minio/minio (Go): affected from 0.0.0-20240328174456-468a9fae83e9 up to 0.0.0-20260212201848-7aac2a2c5b7c; no fix listed
- github.com/minio/minio (Go): affected from 0.0.0-20240328174456-468a9fae83e9 up to 0.0.0-20260212201848-7aac2a2c5b7c; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34204/ (Markdown: https://insights.sbomify.com/CVE-2026-34204/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34204
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34204
- OSV: https://osv.dev/vulnerability/CVE-2026-34204

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34204/
Summaries are generated and may contain mistakes; the official description above is the record.