CVE-2026-41145

April 22, 2026, 9:23 p.m.

8.8
High

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 `STREAMING-UNSIGNED-PAYLOAD-TRAILER` code path 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. `PutObjectHandler` and `PutObjectPartHandler` call `newUnsignedV4ChunkedReader` with a signature verification gate based solely on the presence of the `Authorization` header. Meanwhile, `isPutActionAllowed` extracts credentials from either the `Authorization` header or the `X-Amz-Credential` query parameter, and trusts whichever it finds. An attacker omits the `Authorization` header and supplies credentials exclusively via the query string. The signature gate evaluates to `false`, `doesSignatureMatch` is never called, and the request proceeds with the permissions of the impersonated access key. This affects `PutObjectHandler` (standard and tables/warehouse bucket paths) and `PutObjectPartHandler` (multipart uploads). 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.

Product(s) Impacted

Vendor Product Versions
Minio
  • Minio
  • RELEASE.2023-05-18T00-05-36Z-RELEASE.2026-04-11T03-20-12Z

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-287
Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a minio minio RELEASE.2023-05-18T00-05-36Z-RELEASE.2026-04-11T03-20-12Z / / / / / / /

References

https://github.com/minio/minio/commit/76913a9fd5c6e5c2dbd4e8c7faf56ed9e9e24091
https://github.com/minio/minio/pull/16484
https://github.com/minio/minio/security/advisories/GHSA-hv4r-mvr4-25vw

Tags

[email protected]
CWE-287
2026-04-22
CVE-2026-41145

CVSS Score

8.8 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Attack Requirements: NONE
  • Privileges Required: NONE
  • User Interaction: NONE
  • Scope:
  • Confidentiality Impact: NONE
  • Integrity Impact: HIGH
  • Availability Impact: LOW
  • Exploit Maturity: NOT_DEFINED

    • 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

    View Vector String

Timeline

Published: April 22, 2026, 1:16 a.m.
Last Modified: April 22, 2026, 9:23 p.m.

Status : Undergoing Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.