Security Digest · Vulnerability record
CVE-2026-33322: MinIO has JWT Algorithm Confusion in OIDC Authentication
MinIO is a high-performance object storage system.
CVSS 9.2 Critical EPSS 0.6% · p49
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.6%, percentile 49: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 49% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
github.com/minio/minio(Go) <= 0.0.0-20260212201848-7aac2a2c5b7c, no fixed version listed. Check your lockfile, including transitive dependencies.
What it is
MinIO is a high-performance object storage system. From RELEASE.2022-11-08T05-27-07Z to before RELEASE.2026-03-17T21-25-16Z, 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. This issue has been patched in RELEASE.2026-03-17T21-25-16Z.
From the GitHub advisory
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).
Weakness type: CWE-287, CWE-327.
Product: github.com/minio/minio (Go) · Assigned by: GitHub_M · Published: 2026-03-24
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/minio/minio | <= 0.0.0-20260212201848-7aac2a2c5b7c | none listed |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| minio | minio | >= RELEASE.2022-11-08T05-27-07Z, < RELEASE.2026-03-17T21-25-16Z |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 9.2 Critical | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| GitHub | 4.0 | 9.2 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: present (depends on deployment conditions)
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.63% probability of exploitation activity in the next 30 days; percentile 49.
Timeline
- — GitHub-reviewed advisory GHSA-5cx5-wh4m-82fh published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-5cx5-wh4m-82fh github.com
- CVE.org record CVE-2026-33322 cve.org
- NVD entry CVE-2026-33322 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com