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CVE-2026-55189highCWE-862CWE-863

RustFS: FTP frontend skips IAM authorization on object reads

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.7epss 0.3%
exploitation probability
0.3%top 72% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Affected products
rustfs · rustfs