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)
HAS_WEAKNESS (2)
AFFECTS (1)
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