CVE-2026-39360
RustFS has an authorization bypass in multipart UploadPartCopy enables cross-bucket object exfiltration
Description
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.
CVSS Vector Breakdown
AV:NAttack VectorAC:LAttack ComplexityPR:LPrivileges RequiredUI:NUser InteractionS:UScopeC:LConfidentialityI:NIntegrityA:NAvailabilityWeaknesses
Affected Products
Attack Graph
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Exploitability
MITRE ATT&CK
2 techniquesReferences
Timeline
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