# MinIO: Security Feature Bypass (CVE-2023-28434) · pwn.watch

> 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. Added to CISA KEV on 2023-09-19.

Page: https://pwn.watch/i/minio-cve-2023-28434 · generated 2026-10-22T20:45:43.249Z

## Status
- Severity: high · status: closed · patch: patched
- Product: MinIO
- Started: 2023-09-19 · closed: 2023-09-19
- CVEs: CVE-2023-28434
- Affected: See vendor advisory / CISA notes (versions not always listed in KEV feed)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/minio-cve-2023-28434/feed.xml
- JSON Feed: https://pwn.watch/i/minio-cve-2023-28434/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/minio-cve-2023-28434.json
- This file: https://pwn.watch/i/minio-cve-2023-28434/llms.txt

## Updates (newest first)
- 2023-09-19: CISA added CVE-2023-28434 to the KEV catalog (due 2023-10-10).

## Fix brief
# Security brief: MinIO: Security Feature Bypass (CVE-2023-28434)

Source: https://pwn.watch/i/minio-cve-2023-28434 · status: closed (closed Sep 19, 2023) · severity: high · updated Sep 19, 2023

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
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. Added to CISA KEV on 2023-09-19.

Severity detail: CVSS 8.8 (NVD), actively exploited (CISA KEV)

- Product: MinIO
- CVE / advisory ids: CVE-2023-28434

## Affected versions
- See vendor advisory / CISA notes (versions not always listed in KEV feed)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Secrets to rotate
This incident involves possible credential exposure. Rotate any credentials (API keys, tokens, env vars, SSH keys) that were present on affected systems or in affected builds while vulnerable/compromised versions were installed, and review access logs.

## Latest updates
- Sep 19, 2023: CISA added CVE-2023-28434 to the KEV catalog (due 2023-10-10).

## Advisories
- [Vendor advisory: MinIO](https://github.com/minio/minio/security/advisories/GHSA-2pxw-r47w-4p8c) (MinIO)
- [NVD: CVE-2023-28434](https://nvd.nist.gov/vuln/detail/CVE-2023-28434) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from CISA KEV JSON feed catalogVersion 2026.10.21. Exact affected/fixed version strings are not always in the KEV record — verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier).

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Machine-readable: https://pwn.watch/i/minio-cve-2023-28434.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.