MinIO performs incomplete signature validation for unsigned-trailer uploads
### Impact This is a high priority vulnerability and users must upgrade ASAP. The signature component of the authorization may be invalid, which would mean that as a client you can use any arbitrary secret to upload objects given the user already has prior WRITE permissions on the bucket, Prior knowledge of access-key, and bucket name this user might have access to - and an access-key with a WRITE permissions is necessary. However with relevant information in place, uploading random objects to buckets is trivial and easy via `curl` ### Patches Yes https://github.com/minio/minio/pull/21103 ### Workarounds Reject requests with `x-amz-content-sha256: STREAMING-UNSIGNED-PAYLOAD-TRAILER` for now at LB layer, ask application users to use `STREAMING-AWS4-HMAC-SHA256-PAYLOAD-TRAILER`
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-31489US | — | — | ||
MinIO is a High Performance Object Storage released under GNU Affero General Public License v3.0. The signature component of the authorization may be invalid, which would mean that… | ||||
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