CVE-2026-45042 HIGH

CVE-2026-45042: RustFS: UploadPartCopy Does Not Enforce Destination Bucket Policy on Copy Source

Vendor Rustfs
Product rustfs
Weakness CWE-863 · Incorrect authorization
Published May 28, 2026
Last update May 28, 2026

CVSS base score

7.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

RustFS is a distributed object storage system built in Rust. Prior to 1.0.0-beta.2, improper authorization in the UploadPartCopy operation allows copying objects across buckets without enforcing destination bucket restrictions on allowed copy sources. The implementation validates GetObject permission on the source bucket and PutObject on the destination bucket independently, but does not enforce any policy constraints on whether the destination bucket permits the specified copy source. This enables unauthorized cross-bucket data movement. This vulnerability is fixed in 1.0.0-beta.2.

Key dates

02Disclosure timeline

May 28, 2026 CVE published
May 28, 2026 Record updated