Upstream information

CVE-2026-40344 at MITRE

Description

MinIO is a high-performance object storage system. Starting in RELEASE.2023-05-18T00-05-36Z and prior to RELEASE.2026-04-11T03-20-12Z, an authentication bypass vulnerability in MinIO's Snowball auto-extract handler (`PutObjectExtractHandler`) allows any user who knows a valid access key to write arbitrary objects to any bucket without knowing the secret key or providing a valid cryptographic signature. Any MinIO deployment is impacted. The attack requires only a valid access key (the well-known default `minioadmin`, or any key with WRITE permission on a bucket) and a target bucket name. When `authTypeStreamingUnsignedTrailer` support was added, the new auth type was handled in `PutObjectHandler` and `PutObjectPartHandler` but was never added to `PutObjectExtractHandler`. The snowball auto-extract handler's `switch rAuthType` block has no case for `authTypeStreamingUnsignedTrailer`, so execution falls through with zero signature verification. The `isPutActionAllowed` call before the switch extracts the access key and checks IAM permissions, but does not verify the cryptographic signature. An attacker sends a PUT request with `X-Amz-Content-Sha256: STREAMING-UNSIGNED-PAYLOAD-TRAILER`, `X-Amz-Meta-Snowball-Auto-Extract: true`, and an `Authorization` header containing a valid access key with a completely fabricated signature. The request is accepted and the tar payload is extracted into the bucket. Users of the open-source minio/minio project should upgrade to MinIO AIStor RELEASE.2026-04-11T03-20-12Z or later. If upgrading is not immediately possible, block unsigned-trailer requests at the load balancer. Reject any request containing X-Amz-Content-Sha256: STREAMING-UNSIGNED-PAYLOAD-TRAILER at the reverse proxy or WAF layer. Clients can use STREAMING-AWS4-HMAC-SHA256-PAYLOAD-TRAILER (the signed variant) instead. Alternatively, restrict WRITE permissions. Limit s3:PutObject grants to trusted principals. While this reduces the attack surface, it does not eliminate the vulnerability since any user with WRITE permission can exploit it with only their access key.

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having important severity.

CVSS v3 Scores
CVSS detail National Vulnerability Database
Base Score 8.2
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact High
Availability Impact Low
CVSSv3 Version 3.1
CVSS v4 Scores
CVSS detail CNA (GitHub)
Base Score 8.8
Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User Interaction None
Vulnerable System Confidentiality Impact None
Vulnerable System Integrity Impact High
Vulnerable System Availability Impact Low
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
CVSSv4 Version 4.0
No SUSE Bugzilla entries cross referenced.

No SUSE Security Announcements cross referenced.

List of released packages

Product(s) Fixed package version(s) References


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Server 16.1 govulncheck-vulndb Released
SUSE Linux Enterprise Server for SAP applications 16.1 govulncheck-vulndb Released
Products past their end of life and not receiving proactive updates anymore.
SUSE Linux Enterprise Module for Package Hub 15 SP5 govulncheck-vulndb Affected
SUSE Linux Enterprise Module for Package Hub 15 SP6 govulncheck-vulndb Affected
openSUSE Leap 15.5 govulncheck-vulndb Affected
openSUSE Leap 15.6 govulncheck-vulndb Affected


SUSE Timeline for this CVE

CVE page created: Thu Jul 30 15:07:06 2026
CVE page last modified: Sat Aug 1 11:34:59 2026