CVE-2021-41137Public exploitNetwork attack vector

Authenticated policy bypass via incorrect owner flag

Published Oct 13, 2021 · Updated Aug 4, 2024

Improper authorization in MinIO RELEASE.2021-10-10T16-53-30Z allows remote authenticated users to bypass assigned IAM policy restrictions. The checkKeyValid function initializes the owner flag as true and leaves it true for regular credentials without session claims, causing downstream authorization to treat those users as owners. A regular account without service-account or STS credentials is required, and the bypass exposes owner-authorized storage and administrative operations outside its assigned policy.

CVSS severity8.8
High
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in MinIO RELEASE.2021-10-10T16-53-30Z allows remote authenticated users to bypass assigned IAM policy restrictions. The checkKeyValid function initializes the owner flag as true and leaves it true for regular credentials without session claims, causing downstream authorization to treat those users as owners. A regular account without service-account or STS credentials is required, and the bypass exposes owner-authorized storage and administrative operations outside its assigned policy.

The record

CVE
CVE-2021-41137
Published
Oct 13, 2021
Updated
Aug 4, 2024
Vendor
MinIO
Product
MinIO
Classifications
CWE-285, T1078
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion== RELEASE.2021-10-10T16-53-30Z

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MinIO · MinIOversion== RELEASE.2021-10-10T16-53-30Z

Published CVSS scores

8.8GitHub CNACVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-285Improper Authorization
T1078Valid Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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