CVE-2026-33419
ADVISORY - githubSummary
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:
- User Enumeration via Distinguishable Error Messages (CWE-204)
- Missing Rate Limiting on STS Authentication Endpoints (CWE-307)
When exploited together, an attacker can:
- Enumerate valid LDAP usernames by observing error message differences.
- Perform high-speed password brute-force attacks against confirmed valid users.
- 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=AssumeRoleWithLDAPIdentityendpoint. - 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.
GitHub
CVSS SCORE
9.1critical| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| github.com/minio/minio | golang | - | - | <=0.0.0-20260212201848-7aac2a2c5b7c | Not yet available |
CVSS:4 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.
The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: A race condition must be won to successfully exploit the vulnerability. The successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker. The attack may need to be launched multiple times against a single target before being successful. Network injection. The attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges.
There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the Vulnerable System. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the Vulnerable System.
There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
There is no impact to availability within the Vulnerable System.
There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
NIST
CVSS SCORE
9.1criticalGoLang
-
Bitnami
BIT-minio-2026-33419
-
CVSS SCORE
9.1criticalChainguard
CGA-v2p2-3345-hp4g
-
minimos
MINI-332m-jx4w-xqgc
-
minimos
MINI-q8w4-wxgw-6h7p
-