CVE-2026-39360 RustFS has an authorization bypass in multipart UploadPartCopy enables cross-bucket object exfiltration
A missing authorization check in RustFS allows low-privileged users to exfiltrate objects from other buckets via multipart copy operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-39360?
CVE-2026-39360 is a medium-severity missing authorization vulnerability in rustfs, published on 7 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-862
Which versions are affected by CVE-2026-39360?
2 open source packages ship an affected version, including rustfs. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
rustfs crates.io | All versions to 0.0.2 | None |
rustfs crates.io | All versions to 0.0.2 | None |
Products include Rustfs Rustfs.
How do I fix CVE-2026-39360?
No fix has been published for CVE-2026-39360 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-39360 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39360 exists.
Other vulnerabilities in rustfs
- CVE-2025-68926 RustFS has a gRPC Hardcoded Token Authentication Bypass
- CVE-2026-27822 Rust has Critical Stored XSS in Preview Modal, leading to Administrative Account Takeover
- CVE-2025-68705 RustFS Path Traversal Vulnerability
- CVE-2026-40937 RustFS: Missing admin authorization on notification target endpoints allows unauthenticated configuration of event webhooks
- CVE-2026-27607 RustFS's Missing Post Policy Validation leads to Arbitrary Object Write
Sources
Also known as GHSA-mx42-j6wv-px98.