CVE-2021-43858

HIGH

MinIO <RELEASE.2021-12-27T07-23-18Z - Privilege Escalation

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2021-43858. PoCs published by khuntor.

AI-analyzed exploit summary This Go-based exploit demonstrates CVE-2021-43858, a privilege escalation vulnerability in MinIO. It creates a new admin user by exploiting improper access control in the MinIO admin API.

Description

MinIO is a Kubernetes native application for cloud storage. Prior to version `RELEASE.2021-12-27T07-23-18Z`, a malicious client can hand-craft an HTTP API call that allows for updating policy for a user and gaining higher privileges. The patch in version `RELEASE.2021-12-27T07-23-18Z` changes the accepted request body type and removes the ability to apply policy changes through this API. There is a workaround for this vulnerability: Changing passwords can be disabled by adding an explicit `Deny` rule to disable the API for users.

Exploits (2)

nomisec WORKING POC
by khuntor · poc
https://github.com/khuntor/CVE-2021-43858-MinIO

This Go-based exploit demonstrates CVE-2021-43858, a privilege escalation vulnerability in MinIO. It creates a new admin user by exploiting improper access control in the MinIO admin API.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: MinIO (versions affected by CVE-2021-43858)
No auth needed
Prerequisites: Network access to MinIO admin interface · MinIO instance vulnerable to CVE-2021-43858
devstral-2 · analyzed Feb 16, 2026 Full analysis →
inthewild WORKING POC
poc
https://github.com/0rx1/cve-2021-43858

This repository contains a functional Go-based exploit for CVE-2021-43858, a privilege escalation vulnerability in MinIO. The exploit crafts a malicious HTTP request to elevate a user's privileges to 'consoleAdmin' by manipulating the MinIO admin API.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: MinIO (version not specified)
Auth required
Prerequisites: valid MinIO instance URL · existing user credentials (accessKey and secretKey)
devstral-2 · analyzed Feb 23, 2026 Full analysis →

References (5)

Core 5
Core References
Patch, Third Party Advisory x_refsource_confirm
https://github.com/minio/minio/security/advisories/GHSA-j6jc-jqqc-p6cx
Patch, Third Party Advisory x_refsource_misc
https://github.com/minio/minio/pull/13976
Patch, Third Party Advisory x_refsource_misc
https://github.com/minio/minio/pull/7949
Release Notes, Third Party Advisory x_refsource_misc
https://github.com/minio/minio/releases/tag/RELEASE.2021-12-27T07-23-18Z

Scores

CVSS v3 8.8
EPSS 0.5312
EPSS Percentile 98.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-269 CWE-863
Status published
Products (1)
minio/minio < 2021-12-27t07-23-18z
Published Dec 27, 2021
Tracked Since Feb 18, 2026