CVE-2026-39360 — RustFS has an authorization bypass in multipart UploadPartCopy enables cross-bucket object exfiltration

CVE-2026-39360

RustFS has an authorization bypass in multipart UploadPartCopy enables cross-bucket object exfiltration PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
rustfs / rustfs	affected < alpha.90

CWE

CWE-862

References

https://github.com/rustfs/rustfs/security/advisories/GHSA-mx42-j6wv-px98

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.