CVE-2026-33419

MinIO: LDAP login brute-force via user enumeration and missing rate limit

State: Published
Severity: 9.1 Critical
Published: Mar 24, 2026
Updated: Mar 25, 2026
Reserved: Mar 19, 2026

Description

MinIO is a high-performance object storage system. Prior to RELEASE.2026-03-17T21-25-16Z, MinIO AIStor's STS (Security Token Service) AssumeRoleWithLDAPIdentity endpoint is vulnerable to LDAP credential brute-forcing due to two combined weaknesses: (1) distinguishable error responses that enable username enumeration, and (2) absence of rate limiting on authentication attempts. An unauthenticated network attacker can enumerate valid LDAP usernames and then perform unlimited password guessing to obtain temporary AWS-style STS credentials, gaining access to the victim's S3 buckets and objects. This issue has been patched in RELEASE.2026-03-17T21-25-16Z.

Scores

CVSS	Score	Vector	Source
4.0	9.1 Critical	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-204 Observable Response Discrepancy
CWE-307 Improper Restriction of Excessive Authentication Attempts

Affected Products

Product	Versions
miniominio	< RELEASE.2026-03-17T21-25-16ZAffected

References

https://github.com/minio/minio/security/advisories/GHSA-jv87-32hw-hh99

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