---
id: "CVE-2023-28434"
kind: "vulnerability"
aliases: ["CVE-2023-28434"]
title: "Minio is a Multi-Cloud Object Storage framework"
severity: "high"
cvss: 8.8
epss: null
exploited: true
status: "open"
category: "package"
products: [{"name": "MinIO MinIO", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "minio", "fixed": ["2023-03-20t20-16-18z"], "affected": "< 2023-03-20t20-16-18z", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "minio", "package", "s3-compatible-storage", "self-hosted"]
not_affected_if: ["managed-hosting", "no-console-api", "no-wildcard-s3-credentials"]
published_at: "2023-03-22T21:15:18+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-28434", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-28434", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# Minio is a Multi-Cloud Object Storage framework

MinIO, a self-hosted S3-compatible object store, has a flaw in PostPolicyBucket handling that lets a user write objects into any bucket. An attacker with credentials that already hold broad s3 permissions can escalate privileges and reach data they should not access.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:MinIO MinIO affected ? fixed ?
- vendor:minio affected < 2023-03-20t20-16-18z fixed 2023-03-20t20-16-18z

## How to check

Check whether the Console API is enabled on your MinIO deployment (look for the console listener or MINIO_BROWSER settings).
List IAM users and policies and look for any with arn:aws:s3:::* permissions.

## Fix

Upgrade MinIO to a release that includes the fix for CVE-2023-28434 (the fixed version is not stated in the sources).
Until patched, disable Console API access and restrict credentials that hold arn:aws:s3:::* permissions.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-28434
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-28434

## From the sources

MinIO contains a security feature bypass vulnerability that allows an attacker to use crafted requests to bypass metadata bucket name checking and put an object into any bucket while processing `PostPolicyBucket` to conduct privilege escalation. To carry out this attack, the attacker requires credentials with `arn:aws:s3:::*` permission, as well as enabled Console API access.

CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_