CRITICALCVSS 9.8Vulnerability

CVE-2026-33322

### Impact _What kind of vulnerability is it? Who is impacted?_ A JWT algorithm confusion vulnerability in MinIO's OpenID Connect authentication allows an attacker who knows the OIDC `ClientSecret` to forge arbitrary identity tokens and obtain S3 credentials with any policy, including `consoleAdmin`. An attacker with knowledge of the OIDC `ClientSecret` can: - Impersonate any user identity - Obtain S3 credentials with any IAM policy, including `consoleAdmin` - Access, modify, or delete any data in the MinIO deployment The attack is deterministic (100% success rate, no race conditions). #### Attack Prerequisites The attacker must know the OIDC `ClientSecret`. While this is a shared credential (not a private key), it is more accessible than commonly assumed: - CVE-2023-28432 previously leaked environment variables including `MINIO_IDENTITY_OPENID_CLIENT_SECRET` - Client secrets are often present in frontend OAuth configurations, mobile app bundles, CI/CD pipelines, and shared configuration files - In many organizations, the client secret is accessible to operators and engineers who should not be able to forge arbitrary identities #### Affected Versions All MinIO releases from `RELEASE.2022-11-08T05-27-07Z` through the final release of the `minio/minio` open-source project. ### Patches **Fixed in:** MinIO AIStor `RELEASE.2026-03-17T21-25-16Z` ## Downloads ### Binary Downloads | Platform | Architecture | Download | | -------- | ------------ | --------------------------------------------------------------------------- | | Linux | amd64 | [minio](https://dl.min.io/aistor/minio/release/linux-amd64/minio) | | Linux | arm64 | [minio](https://dl.min.io/aistor/minio/release/linux-arm64/minio) | | macOS | arm64 | [minio](https://dl.min.io/aistor/minio/release/darwin-arm64/minio) | | macOS | amd64 | [minio](https://dl.min.io/aisto

Properties

Summary
MinIO has JWT Algorithm Confusion in OIDC Authentication
Severity
CRITICAL
Cvss score
9.8
Epss score
0.00629
Retrieved at
2026-10-23T18:31:18+00:00
Ghsa published
2026-03-19T17:56:37Z
Source url
https://github.com/advisories/GHSA-5cx5-wh4m-82fh
Ghsa updated
2026-03-27T21:57:21Z
Ghsa id
GHSA-5cx5-wh4m-82fh
Last source
FIRST EPSS
Cve id
CVE-2026-33322
Cvss vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
In Signal since
initial import (Sep 2026)
Name
CVE-2026-33322
Is ghsa only
false
Epss percentile
0.49532

Related Entities (3)

AFFECTS (1)

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CVE-2026-33322 (CVSS 9.8) — Ninja Signal Threat Intelligence | Ninja Signal