CVE-2026-55189

Description

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 v3.1 Score

7.7

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.10%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

CWE-863 Incorrect Authorization

References

Other References

https://github.com/rustfs/rustfs/security/advisories/GHSA-3g29-xff2-92vp https://github.com/rustfs/rustfs/security/advisories/GHSA-3g29-xff2-92vp

Frequently Asked Questions

What is CVE-2026-55189? +

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. It has a CVSS v3.1 base score of 7.7 (HIGH).

How severe is CVE-2026-55189? +

CVE-2026-55189 has a CVSS v3.1 score of 7.7 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55189? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-40570

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, the `load_customer_info` action in `POST /conversation/ajax` …

CVE-2026-42317

GLPI is a free asset and IT management software package. Starting in version 0.78 and prior to versions 10.0.25 and …

CVE-2026-4881

In affected versions of Octopus Server, permissions were not checked correctly resulting in any authenticated user being able to make …

CVE-2026-40543

SOPlanning does not enforce authorization for backup functionalities. An unauthenticated attacker can directly query backup-related endpoints and retrieve backup archives …

CVE-2026-10831

A denial-of-service vulnerability exists in NPort devices because of improper access control on the command port. The command interface does …

CVE-2026-40314

NamelessMC is website software for Minecraft servers. In version 2.2.4,`core/classes/Misc/ProfilePostReactionContext.php` only verifies that the wall post exists and does not …