Vulnerability Details CVE-2026-39360
RustFS is a distributed object storage system built in Rust. Prior to alpha.90, RustFS contains a missing authorization check in the multipart copy path (UploadPartCopy). A low-privileged user who cannot read objects from a victim bucket can still exfiltrate victim objects by copying them into an attacker-controlled multipart upload and completing the upload. This breaks tenant isolation in multi-user / multi-tenant deployments. This vulnerability is fixed in alpha.90.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 11.6%
CVSS Severity
CVSS v3 Score 4.3