MinIO is Vulnerable to SSE Metadata Injection via Replication Headers

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

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 · score source

EPSS

• CVE-2026-34204: 0.13% estimated exploitation activity in the next 30 days; percentile 2.54 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

27 Mar 2026, 22:26 UTC

Last modified by the source

8 Apr 2026, 11:55 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3rh2-v3gr-35p9

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# Patch Next advisory brief: CVE-2026-34204

Advisory: MinIO is Vulnerable to SSE Metadata Injection via Replication Headers
IDs: CVE-2026-34204, GHSA-3rh2-v3gr-35p9
Record: https://patchnext.com/advisories/cve-2026-34204 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/minio/minio: affected >= 0.0.0-20240328174456-468a9fae83e9, <= 0.0.0-20260212201848-7aac2a2c5b7c

## Suggested inspection (read-only)
- Go github.com/minio/minio: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/minio/minio.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3rh2-v3gr-35p9 (GitHub-reviewed advisory GHSA-3rh2-v3gr-35p9 lists affected ranges: Go github.com/minio/minio >=0.0.0-20240328174456-468a9fae83e9 <=0.0.0-20260212201848-7aac2a2c5b7c)

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