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.
{
"cwe_ids": [
"CWE-862",
"CWE-863"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55189.json",
"cna_assigner": "GitHub_M"
}