Headline
GHSA-wg47-6jq2-q2hh: 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
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 minio/minio#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
References
- GHSA-wg47-6jq2-q2hh
- https://nvd.nist.gov/vuln/detail/CVE-2025-31489
- minio/minio#21103
- minio/minio@8c70975