CVE-2025-31489: 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
Other sources
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 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. This issue is fixed in RELEASE.2025-04-03T14-56-28Z.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-31489?
CVE-2025-31489 has a high severity rating due to the risk of unauthorized object uploads.
How do I fix CVE-2025-31489?
To fix CVE-2025-31489, upgrade to a version of MinIO released after April 3, 2025.
What components of MinIO are impacted by CVE-2025-31489?
CVE-2025-31489 affects the signature component of MinIO's authorization process.
Can CVE-2025-31489 be exploited without authentication?
Yes, if a user has write permissions, CVE-2025-31489 can be exploited using arbitrary secrets.
Is there a workaround for CVE-2025-31489 before upgrading?
There are no documented workarounds; upgrading to a secure version is the recommended action.