GHSA-JV87-32HW-HH99

Vulnerability from github – Published: 2026-03-20 20:47 – Updated: 2026-03-27 21:59
VLAI?
Summary
MinIO LDAP login brute-force via user enumeration and missing rate limit
Details

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.
  2. Perform high-speed password brute-force attacks against confirmed valid users.
  3. 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
Linux arm64 minio
macOS arm64 minio
macOS amd64 minio
Windows amd64 minio.exe

FIPS Binaries

Platform Architecture Download
Linux amd64 minio.fips
Linux arm64 minio.fips

Package Downloads

Format Architecture Download
DEB amd64 minio_20260317212516.0.0_amd64.deb
DEB arm64 minio_20260317212516.0.0_arm64.deb
RPM amd64 minio-20260317212516.0.0-1.x86_64.rpm
RPM arm64 minio-20260317212516.0.0-1.aarch64.rpm

Container Images

# 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)

brew install minio/aistor/minio

Workarounds

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.
Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/minio/minio"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.0.0-20260212201848-7aac2a2c5b7c"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33419"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-204",
      "CWE-307"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-20T20:47:54Z",
    "nvd_published_at": "2026-03-24T20:16:29Z",
    "severity": "CRITICAL"
  },
  "details": "### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nMinIO AIStor\u0027s 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\u0027s S3 buckets and objects.\n\nAll deployments with LDAP configured running an affected version are impacted.\n\nThere are two vulnerabilities:\n\n1. User Enumeration via Distinguishable Error Messages (CWE-204)\n2. Missing Rate Limiting on STS Authentication Endpoints (CWE-307)\n\nWhen exploited together, an attacker can:\n\n1. Enumerate valid LDAP usernames by observing error message differences.\n3. Perform high-speed password brute-force attacks against confirmed valid users.\n4. Upon finding valid credentials, obtain temporary AWS-style STS credentials (`AccessKeyId`, `SecretAccessKey`, `SessionToken`) with full access to the victim user\u0027s S3 resources.\n\n### Affected Versions\n\nAll MinIO releases through the final release of the minio/minio open-source project.\n\n### Patches\n\n**Fixed in**: MinIO AIStor RELEASE.2026-03-17T21-25-16Z\n\n#### Binary Downloads\n\n| Platform | Architecture | Download                                                                    |\n| -------- | ------------ | --------------------------------------------------------------------------- |\n| Linux    | amd64        | [minio](https://dl.min.io/aistor/minio/release/linux-amd64/minio)           |\n| Linux    | arm64        | [minio](https://dl.min.io/aistor/minio/release/linux-arm64/minio)           |\n| macOS    | arm64        | [minio](https://dl.min.io/aistor/minio/release/darwin-arm64/minio)          |\n| macOS    | amd64        | [minio](https://dl.min.io/aistor/minio/release/darwin-amd64/minio)          |\n| Windows  | amd64        | [minio.exe](https://dl.min.io/aistor/minio/release/windows-amd64/minio.exe) |\n\n#### FIPS Binaries\n\n| Platform | Architecture | Download                                                                    |\n| -------- | ------------ | --------------------------------------------------------------------------- |\n| Linux    | amd64        | [minio.fips](https://dl.min.io/aistor/minio/release/linux-amd64/minio.fips) |\n| Linux    | arm64        | [minio.fips](https://dl.min.io/aistor/minio/release/linux-arm64/minio.fips) |\n\n#### Package Downloads\n\n| Format | Architecture | Download                                                                                                                            |\n| ------ | ------------ | ----------------------------------------------------------------------------------------------------------------------------------- |\n| DEB    | amd64        | [minio_20260317212516.0.0_amd64.deb](https://dl.min.io/aistor/minio/release/linux-amd64/minio_20260317212516.0.0_amd64.deb)         |\n| DEB    | arm64        | [minio_20260317212516.0.0_arm64.deb](https://dl.min.io/aistor/minio/release/linux-arm64/minio_20260317212516.0.0_arm64.deb)         |\n| 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)   |\n| 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) |\n\n#### Container Images\n\n```bash\n# Standard\ndocker pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z\npodman pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z\n\n# FIPS\ndocker pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z.fips\npodman pull quay.io/minio/aistor/minio:RELEASE.2026-03-17T21-25-16Z.fips\n```\n\n#### Homebrew (macOS)\n\n```bash\nbrew install minio/aistor/minio\n```\n \n\n### Workarounds\n\n- [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/)\n\nIf upgrading is not immediately possible:\n\n- **Network-level rate limiting**: Use a reverse proxy (e.g., nginx, HAProxy) or WAF to rate-limit requests to the `/?Action=AssumeRoleWithLDAPIdentity` endpoint.\n- **Firewall restrictions**: Restrict access to the STS endpoint to trusted networks/IP ranges only.\n- **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.",
  "id": "GHSA-jv87-32hw-hh99",
  "modified": "2026-03-27T21:59:08Z",
  "published": "2026-03-20T20:47:54Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/minio/minio/security/advisories/GHSA-jv87-32hw-hh99"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33419"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/minio/minio"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "MinIO LDAP login brute-force via user enumeration and missing rate limit"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…