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MinioApplication

CVE-2026-34204

HIGH · 7.1 CVSS v3.1 Published 2026-03-31
Fix available
A fix is available. Upgrade to 2026-03-26t21-24-40z or later.
See remediation →
77/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A flaw in MinIO's extractMetadataFromMime() function allows any authenticated user with s3:PutObject permission to inject internal server-side encryption metadata into objects by sending crafted X-Minio-Replication-* headers during a normal PutObject request. This metadata injection could allow privilege escalation or manipulation of object encryption settings.

MitigationUpgrade MinIO to version RELEASE.2026-03-26T21-24-40Z or later to patch the vulnerability in extractMetadataFromMime().

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
MinioApplication
Affected:< 2026-03-26t21-24-40z

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check MinIO server version
    Run 'minio version' or examine server startup logs for the RELEASE version string (e.g., RELEASE.2026-01-15T10-30-00Z). Compare against RELEASE.2026-03-26T21-24-40Z.
    Affected if Installed version is earlier than RELEASE.2026-03-26T21-24-40Z.
  2. Identify users with s3:PutObject permission
    Use the MinIO admin API (mc admin policy list) or examine IAM policies to list all users/groups that have the s3:PutObject action permitted.
    Affected if Any user or service account has s3:PutObject permission in your MinIO deployment.
  3. Verify S3 API endpoint accessibility
    Confirm your MinIO S3 API port (default 9000) is reachable and accepts authenticated PutObject requests.
    Affected if The S3 API is exposed and accepts authenticated connections.
  4. Review audit logs for X-Minio-Replication-* headers
    Search MinIO audit logs (mc admin logs or configured log sink) for incoming PutObject requests that contain headers starting with 'X-Minio-Replication-'.
  5. Check if server-side replication or encryption is configured
    Run 'mc replicate ls' or 'mc encrypt info' to see if any buckets have replication rules or encryption policies enabled.
    Affected if Any bucket has active replication rules or SSE-KMS encryption policies configured.

Your environment is affected if you run MinIO version earlier than RELEASE.2026-03-26T21-24-40Z AND have users with s3:PutObject permission able to send arbitrary S3 requests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2026-03-26t21-24-40z or later
Fixed in 2026-03-26t21-24-40z
Interim mitigation

Upgrade MinIO to version RELEASE.2026-03-26T21-24-40Z or later to patch the vulnerability in extractMetadataFromMime().

Recommended fix High confidence

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

  1. 1. Backup your current MinIO deployment configuration and data
  2. 2. Review MinIO upgrade documentation for your deployment method (standalone, distributed, or Kubernetes)
  3. 3. Stop the MinIO service
  4. 4. Update MinIO binaries or container images to version RELEASE.2026-03-26T21-24-40Z
  5. 5. Verify the new version is running: `minio --version`
  6. 6. Start the MinIO service
  7. 7. Test basic operations (PutObject, GetObject) to verify functionality
  8. 8. Verify the fix by attempting to use X-Minio-Replication-* headers and confirming they are rejected for non-admin users
Caveat Review MinIO release notes for RELEASE.2026-03-26T21-24-40Z for any configuration or API changes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Minio Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34204 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data