What is CVE-2026-34204?

CVE-2026-34204 is a high-severity vulnerability in Minio, classified under Improper Authentication. CVSS score: 7.1/10. Published 2026-03-31.

How severe is CVE-2026-34204?

High severity. CVSS v3 base score is 7.1 out of 10.

Auth bypass in Minio

CVE-2026-34204

MinIO is a high-performance object storage system. Prior to version RELEASE.2026-03-26T21-24-40Z, a flaw in extractMetadataFromMime() allows any authenticated user with s3:PutObject permission to inject internal server-side encryption metadata into objects by sending crafted X-Minio-Replication-* headers on a normal PutObject request. This issue has been patched in version RELEASE.2026-03-26T21-24-40Z.

Vulnerability class: Broken Authentication

EPSS: 0.001 (2.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H.

Affected products

Minio — versions < RELEASE.2026-03-26T21-24-40Z

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-34204?: CVE-2026-34204 is a high-severity vulnerability in Minio, classified under Improper Authentication. CVSS score: 7.1/10. Published 2026-03-31.
How severe is CVE-2026-34204?: High severity. CVSS v3 base score is 7.1 out of 10.