Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 10 Oct 2023.
MinioApplication

CVE-2023-28434

HIGH · 8.8 CVSS v3.1 Published 2023-03-22
Fix available
A fix is available. Upgrade to 2023-03-20t20-16-18z or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Public exploit Remotely reachable Zero-click Patch available

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 Multi-Cloud Object Storage framework. Prior to RELEASE.2023-03-20T20-16-18Z, an attacker can use crafted requests to bypass metadata bucket name checking and put an object into any bucket while processing `PostPolicyBucket`. To carry out this attack, the attacker requires credentials with `arn:aws:s3:::*` permission, as well as enabled Console API access. This issue has been patched in RELEASE.2023-03-20T20-16-18Z. As a workaround, enable browser API access and turn off `MINIO_BROWSER=off`.

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

Minio prior to RELEASE.2023-03-20T20-16-18Z contains a bypass in the PostPolicyBucket handler where metadata bucket name checking is insufficient, allowing an authenticated attacker with `arn:aws:s3:::*` permission and Console API access to write objects into buckets they shouldn't have access to.

MitigationUpgrade Minio to RELEASE.2023-03-20T20-16-18Z or later. As a workaround, ensure the browser API is enabled (do not set MINIO_BROWSER=off).

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:< 2023-03-20t20-16-18z

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 query the MinIO server's /minio/health/live or /minio/health/ready endpoint, or inspect the output of `minio admin info`
    Affected if The reported version is earlier than RELEASE.2023-03-20T20-16-18Z
  2. Verify PostPolicyBucket is in use
    Review application logs and configurations for use of the PostPolicyBucket API (also known as presigned POST policy) for object uploads
    Affected if The MinIO deployment uses PostPolicyBucket/presigned POST policy for object uploads
  3. Identify users with broad S3 permissions
    Run `mc admin policy list` (if mc is installed) or query MinIO IAM APIs to enumerate user policies, looking for policies containing `arn:aws:s3:::*` permission
    Affected if Any IAM user or service account has a policy granting `arn:aws:s3:::*` (wildcard) permissions across all buckets
  4. Confirm Console API accessibility
    Check if the MinIO Browser/Console is reachable at the default port 9000 or configured endpoint, and verify the MINIO_BROWSER environment variable setting if accessible
    Affected if The MinIO Console API is accessible and the deployment uses the vulnerable code path for PostPolicyBucket processing

A user is affected if their MinIO version is before RELEASE.2023-03-20T20-16-18Z AND they use PostPolicyBucket with users that have broad `arn:aws:s3:::*` permissions while the Console API is accessible.

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 2023-03-20t20-16-18z or later
Fixed in 2023-03-20t20-16-18z
Vendor patch github.com →
Interim mitigation

Upgrade Minio to RELEASE.2023-03-20T20-16-18Z or later. As a workaround, ensure the browser API is enabled (do not set MINIO_BROWSER=off).

Recommended fix High confidence

RELEASE.2023-03-20T20-16-18Z

  1. Upgrade Minio to RELEASE.2023-03-20T20-16-18Z or later release version

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

Fix this in Minio Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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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-2023-28434 in production — separate from our analysis above.

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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