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Public proof of conceptFix available

CVE-2021-43858

A public proof of concept exists; no exploitation attested.

  • Published2021-12-27
  • Fixed in2021-12-27t07-23-18z
  • WeaknessCWE-269 · CWE-863

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-12-2722:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub
  3. 2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-43858?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-43858?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Minio
BranchAffectedFixed in
2021.x< 2021-12-27t07-23-18z2021-12-27t07-23-18z

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • RHSA-2022:4956 Red Hat Product Security204 products fixed

    Red Hat Security Advisory: Red Hat Advanced Cluster Management 2.5 security updates, images, and bug fixes

  • RHSA-2022:0735 Red Hat Product Security221 products fixed

    Red Hat Security Advisory: Red Hat Advanced Cluster Management 2.4.2 security updates and bug fixes

Full record on NVD

Fix

  1. Update Minio to 2021-12-27t07-23-18z
  2. Vendor fix Red Hat Product Security RHSA-2022:4956 · 204 productsFor Red Hat Advanced Cluster Management for Kubernetes, see the following documentation, which will be updated shortly for this release, for important instructions on installing this release: https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.5/html-…
  3. Vendor fix Red Hat Product Security RHSA-2022:0735 · 221 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.4/html-single/install/index#instal…
  4. Workaround from the vendor Red Hat Product Security RHSA-2022:4956 · 204 productsThere is a workaround for this vulnerability: Changing passwords can be disabled by adding an explicit `Deny` rule to disable the API for users.

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
2 repositories, unverified0rx1/cve-2021-43858khuntor/CVE-2021-43858-MinIO
PoC-in-GitHub

Sources

  • CNACVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.06.5read 2026-10-23
  • CNAweakness (CWE)CWE-269read 2026-10-23
  • NVDweakness (CWE)CWE-863read 2026-10-23
  • FIRST EPSSEPSS score35.5 %read 2026-10-23
  • PoC-in-GitHubproof of concept2read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-12-27
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-43858?

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.

Is CVE-2021-43858 actively exploited?

Active exploitation of CVE-2021-43858 has not been confirmed. Its EPSS score was 35.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-43858?

CVE-2021-43858 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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