CVE-2026-55189: Rustfs

High severity, CVSS 7.7. EPSS: 0.3% chance of exploitation in the next 30 days.

RustFS is a distributed object storage system built in Rust. From 1.0.0-alpha.1 until 1.0.0-beta.9, when the FTP frontend is enabled, the FTP read and probe handlers dispatch directly to the storage backend without ever calling the IAM authorization function that the FTP write/list handlers (and the entire HTTP S3 path) use. As a result, any user who can authenticate to the FTP listener — including a user whose IAM policy contains an explicit Deny on s3:GetObject — can read (RETR) and stat (SIZE/MDTM) any object in any bucket, and probe any bucket (CWD), completely regardless of their IAM policy. This vulnerability is fixed in 1.0.0-beta.9.

Affected products

• Rustfs Rustfs: from 1.0.0-alpha.1, up to and including 1.0.0-beta.8

Published 2026-06-26. Last modified 2026-06-29.