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Critical

LDAP credential brute-force in MinIO AIStor STS AssumeRoleWithLDAPIdentity

IdentifiersCVE-2026-33419CWE-307· Improper Restriction of Excessive…

CVE-2026-33419 affects MinIO AIStor prior to RELEASE.2026-03-17T21-25-16Z. The vulnerability is present in the STS (Security Token Service) AssumeRoleWithLDAPIdentity endpoint and arises from the combination of distinguishable authentication error responses and the absence of rate limiting on authentication attempts. The distinguishable responses allow remote unauthenticated attackers to enumerate valid LDAP usernames, after which the same endpoint can be used to perform unlimited password guessing against those accounts. If valid LDAP credentials are discovered, the attacker can obtain temporary AWS-style STS credentials and use them to access data exposed through the affected MinIO deployment, including S3 buckets and stored objects.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated remote attacker to identify valid LDAP-backed identities, brute-force their passwords, and obtain temporary AWS-style STS credentials. Those credentials can then be used to access the victim's MinIO/S3 resources, resulting in unauthorized disclosure of bucket contents and object data. The provided context indicates high confidentiality and integrity impact, with no stated availability impact.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, reduce exposure of the STS AssumeRoleWithLDAPIdentity endpoint to trusted networks only, place the endpoint behind controls that enforce authentication throttling or rate limiting, and monitor for repeated failed LDAP authentication attempts and username-enumeration patterns. Additional defensive measures include restricting which principals may use LDAP-backed STS flows and applying network-layer protections to limit unauthenticated remote access to the endpoint.

Remediation

Patch, then assume compromise.

Upgrade MinIO AIStor to RELEASE.2026-03-17T21-25-16Z or later, which patches the vulnerable STS AssumeRoleWithLDAPIdentity behavior. Because exploitation can result in issuance of valid temporary STS credentials, organizations should also review logs for suspicious authentication attempts and unexpected STS token issuance, rotate or invalidate affected credentials where applicable, and assess whether unauthorized access to buckets or objects occurred prior to patching.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
MinioAistorapplication
MinioMinioapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-33419
NVD
nvd.nist.gov/vuln/detail/CVE-2026-33419
MITRE CWE · CWE-307
Improper Restriction of Excessive…
Patch
github.com/minio/minio/security/advisories/GHSA-jv87-32hw-hh99