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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.1 · 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 · score source

EPSS

• CVE-2026-33419: 0.46% estimated exploitation activity in the next 30 days; percentile 39.64 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact What kind of vulnerability is it? Who is impacted? 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. All deployments with LDAP configured running an affected version are impacted. There are two vulnerabilities: 1. User Enumeration via Distinguishable Error Messages (CWE-204) 2. Missing Rate Limiting on STS Authentication Endpoints (CWE-307) When exploited together, an attacker can: 1. Enumerate valid LDAP usernames by observing error message differences. 3. Perform high-speed password brute-force attacks against confirmed valid…

Published by the source

20 Mar 2026, 20:47 UTC

Last modified by the source

27 Mar 2026, 21:59 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jv87-32hw-hh99

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-33419

Advisory: MinIO LDAP login brute-force via user enumeration and missing rate limit
IDs: CVE-2026-33419, GHSA-jv87-32hw-hh99
Record: https://patchnext.com/advisories/cve-2026-33419 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/minio/minio: affected <= 0.0.0-20260212201848-7aac2a2c5b7c

## Suggested inspection (read-only)
- Go github.com/minio/minio: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/minio/minio.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jv87-32hw-hh99 (GitHub-reviewed advisory GHSA-jv87-32hw-hh99 lists affected ranges: Go github.com/minio/minio >=0 <=0.0.0-20260212201848-7aac2a2c5b7c)

Commands are suggestions: review each one before running it.