CVE-2026-39360Public exploitNetwork attack vector

Cross-tenant object exfiltration via unchecked multipart copy

Published Apr 7, 2026 · Updated Apr 7, 2026

Missing authorization in RustFS before alpha.90 allows remote authenticated users to exfiltrate objects through multipart copy. In rustfs/src/storage/access.rs, upload_part_copy() returns success without checking source GetObject permission, after which multipart_usecase.rs reads the source object directly. The user needs multipart upload and destination-object permissions only; successful completion exposes private data across buckets or tenants.

CVSS severity5.3
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in RustFS before alpha.90 allows remote authenticated users to exfiltrate objects through multipart copy. In rustfs/src/storage/access.rs, upload_part_copy() returns success without checking source GetObject permission, after which multipart_usecase.rs reads the source object directly. The user needs multipart upload and destination-object permissions only; successful completion exposes private data across buckets or tenants.

The record

CVE
CVE-2026-39360
Published
Apr 7, 2026
Updated
Apr 7, 2026
Vendor
RustFS
Product
RustFS
Classifications
CWE-862, T1530
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< alpha.90

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

RustFS · RustFSversion=< alpha.90

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1530Data from Cloud Storage

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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