CVE-2026-33322: MinIO OIDC JWT algorithm confusion lets ClientSecret holders mint admin creds

Critical 9.2 EPSS 0.4%

MinIO's OpenID Connect login accepts identity tokens signed with the wrong algorithm, so anyone who knows the OIDC ClientSecret can forge a token for any user and obtain S3 credentials with any IAM policy, including consoleAdmin, giving full read, write and delete access to all data. MinIO notes the attack is deterministic and that client secrets are often widely shared (CI/CD, front-end configs) or were leaked by CVE-2023-28432. The open-source minio/minio project is no longer maintained and gets no fix; the fix ships only in MinIO AIStor. Scored CVSS 4.0 9.2 by the CNA and CVSS 3.1 9.8 by NVD.

CVE-2026-33322CVE identifier
9.2CVSS 4.0 base score (critical)
0.4%EPSS: chance of exploitation in the next 30 days (higher than 37% of CVEs)
2026-03-24published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run the affected software and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
Restart every MinIO server process (systemctl restart minio or recreate containers). Then rotate the OIDC ClientSecret and review IAM/STS credentials issued while vulnerable.
If you cannot patch today, apply the temporary mitigation below and patch as soon as possible.

Affected and fixed versions

Affected:

MinIO RELEASE.2022-11-08T05-27-07Z through the final minio/minio open-source release
MinIO AIStor before RELEASE.2026-03-17T21-25-16Z

Fixed in:

MinIO AIStor RELEASE.2026-03-17T21-25-16Z (no fix for the open-source minio/minio project)

Am I affected?

minio --version
mc admin info <alias>
mc admin config get <alias> identity_openid

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

Debian

wget https://dl.min.io/aistor/minio/release/linux-amd64/minio_20260317212516.0.0_amd64.deb
sudo dpkg -i minio_20260317212516.0.0_amd64.deb
sudo systemctl restart minio

Ubuntu

wget https://dl.min.io/aistor/minio/release/linux-amd64/minio_20260317212516.0.0_amd64.deb
sudo dpkg -i minio_20260317212516.0.0_amd64.deb
sudo systemctl restart minio

RHEL, AlmaLinux, Rocky, Oracle

sudo dnf install https://dl.min.io/aistor/minio/release/linux-amd64/minio-20260317212516.0.0-1.x86_64.rpm
sudo systemctl restart minio

Docker images

docker pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z
# FIPS: quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z.fips
# switch the image in compose/Helm values from minio/minio to quay.io/minio/aistor/minio and recreate

Built from source

Replace the binary with https://dl.min.io/aistor/minio/release/linux-amd64/minio (arm64: .../linux-arm64/minio) and restart.
AIStor Free is MinIO's free-license edition for community use; follow MinIO's community-edition upgrade guide.

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

If you cannot patch yet

Treat the OIDC ClientSecret as a highly sensitive credential and keep it away from untrusted parties (MinIO's stated workaround); rotate it if it has been shared widely.
If OpenID Connect login is not needed, removing the identity_openid configuration removes the attack path.

Related vulnerabilities

CVE-2023-28432

Sources

Page generated automatically from official sources on 2026-11-03 18:05 UTC and reviewed by an editor. Always confirm with your vendor's advisory.