RustFS has an authorization bypass in multipart UploadPartCopy enables cross-bucket object exfiltration_CVE-2026-39360

{
    "lastseen": "",
    "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.",
    "published": "2026-04-07T18:58:29.974Z",
    "modified": "2026-04-07T19:28:22.541Z",
    "type": "cve",
    "title": "RustFS has an authorization bypass in multipart UploadPartCopy enables cross-bucket object exfiltration",
    "source": "GitHub_M",
    "references": "https://github.com/rustfs/rustfs/security/advisories/GHSA-mx42-j6wv-px98",
    "id": "CVE-2026-39360",
    "bulletinFamily": "",
    "cwe": [
        "CWE-862"
    ],
    "cvelist": null,
    "sourceData": "rustfs rustfs < alpha.90",
    "sourceHref": "",
    "cvss": {
        "score": 5.3,
        "severity": "MEDIUM",
        "vector": "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",
        "version": "4.0"
    },
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    "href": "",
    "category_name": "CVE",
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    "product": "rustfs",
    "version": "< alpha.90",
    "vendor": "rustfs",
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