{"id":"CVE-2026-41145","revision":"02102aebedf54642851636a7eb01c5e4","records":[{"revision":"02102aebedf54642851636a7eb01c5e4","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-41145","aliases":[],"title":"MinIO has an Unauthenticated Object Write via Query-String Credential Signature Bypass in Unsigned-Trailer Uploads","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\nallows 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\n`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.","state":0,"publishedAt":"2026-04-22T00:54:09.213+00:00","modifiedAt":"2026-04-22T14:21:43.972+00:00","affected":[{"ecosystem":"Vendor product","name":"minio","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"minio\",\n                    \"product\": \"minio\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= RELEASE.2023-05-18T00-05-36Z, < RELEASE.2026-04-11T03-20-12Z\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","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","score":8.8,"severity":"HIGH"}],"references":["https://github.com/minio/minio/security/advisories/GHSA-hv4r-mvr4-25vw","https://github.com/minio/minio/pull/16484","https://github.com/minio/minio/commit/76913a9fd5c6e5c2dbd4e8c7faf56ed9e9e24091"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-41145","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-41145","identifiers":["CVE-2026-41145"]},"retained":false,"historicalAffected":[]}],"coverage":[]}