CVE-2026-33419 — Vulnerability in github.com/minio/minio — CVE Details
CRITICAL
MinIO LDAP login brute-force via user enumeration and missing rate limit
Published March 20, 2026Updated October 8, 2026Source: osv
Summary
### 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 users.
4. Upon finding valid credentials, obtain temporary AWS-style STS credentials (`AccessKeyId`, `SecretAccessKey`, `SessionToken`) with full access to the victim user's S3 resources.
### Affected Versions
All MinIO releases through the final release of the minio/minio open-source project.
### Patches
**Fixed in**: MinIO AIStor RELEASE.2026-03-17T21-25-16Z
#### 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/aistor/minio/release/darwin-amd64/minio) |
| Windows | amd64 | [minio.exe](https://dl.min.io/aistor/minio/release/windows-amd64/minio.exe) |
#### FIPS Binaries
| Platform | Architecture | Download |
| -------- | ------------ | --------------------------------------------------------------------------- |
| Linux | amd64 | [minio.fips](https://dl.min.io/aistor/minio/release/linux-amd64/minio.fips) |
| Linux | arm64 | [minio.fips](https://dl.min.io/aistor/minio/release/linux-arm64/minio.fips) |
#### Package Downloads
| Format | Architecture | Download |
| ------ | ------------ | ----------------------------------------------------------------------------------------------------------------------------------- |
| DEB | amd64 | [minio_20260317212516.0.0_amd64.deb](https://dl.min.io/aistor/minio/release/linux-amd64/minio_20260317212516.0.0_amd64.deb) |
| DEB | arm64 | [minio_20260317212516.0.0_arm64.deb](https://dl.min.io/aistor/minio/release/linux-arm64/minio_20260317212516.0.0_arm64.deb) |
| RPM | amd64 | [minio-20260317212516.0.0-1.x86_64.rpm](https://dl.min.io/aistor/minio/release/linux-amd64/minio-20260317212516.0.0-1.x86_64.rpm) |
| RPM | arm64 | [minio-20260317212516.0.0-1.aarch64.rpm](https://dl.min.io/aistor/minio/release/linux-arm64/minio-20260317212516.0.0-1.aarch64.rpm) |
#### Container Images
```bash
# Standard
docker pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z
podman pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z
# FIPS
docker pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z.fips
podman pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z.fips
```
#### Homebrew (macOS)
```bash
brew install minio/aistor/minio
```
### Workarounds
- [Users of the open-source `minio/minio` project should upgrade to MinIO AIStor `RELEASE.2026-03-17T21-25-16Z` or later.](https://docs.min.io/enterprise/aistor-object-store/upgrade-aistor-server/community-edition/)
If upgrading is not immediately possible:
- **Network-level rate limiting**: Use a reverse proxy (e.g., nginx, HAProxy) or WAF to rate-limit requests to the `/?Action=AssumeRoleWithLDAPIdentity` endpoint.
- **Firewall restrictions**: Restrict access to the STS endpoint to trusted networks/IP ranges only.
- **LDAP account lockout**: Configure account lockout policies on the LDAP server itself (e.g., Active Directory lockout threshold). Note: this protects against brute-force but not enumeration, and may cause denial-of-service for legitimate users.
Advisory Timeline
- First published March 20, 2026 (206 days ago).
- Last revised October 8, 2026 — 201 days after initial publication.
Affected Packages (1)
Affects 1 ecosystem: go (1).
| Package | Ecosystem | Affected | Fixed In |
|---|---|---|---|
| github.com/minio/minio | go | All versions | Range-based data available |
Vulnerability Classification
Common Weakness Enumeration (CWE) identifiers for this vulnerability type.
- CWE-204
- CWE-307
CVSS Score Breakdown
What the CVSS (Common Vulnerability Scoring System) 8.6 score means for each attack dimension.
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
—
Confidentiality
—
Integrity
—
Availability
—
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
References
Frequently Asked Questions
- What is CVE-2026-33419?
- MinIO LDAP login brute-force via user enumeration and missing rate limit This vulnerability has been assigned a severity rating of CRITICAL (CVSS score: 8.6/10).
- How do I check if my project is affected by CVE-2026-33419?
- CVE-2026-33419 affects github.com/minio/minio. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-33419 and 200,000+ other known vulnerabilities.
Severity & Exploitability
CVSS Score
8.6
High exploitability or significant impact. Prioritize remediation within days.
Also Known As
GHSA-jv87-32hw-hh99
GO-2026-4803
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