Auth bypass in Rustfs

CVE-2026-55188

RustFS is a distributed object storage system built in Rust. From 1.0.0-alpha.1 until 1.0.0-beta.9, RustFS contains an authorization bypass in the bucket replication admin API. The ListRemoteTargetHandler handler for listing remote replication targets only checks whether request credentials exist, but does not verify that the caller has replication or administrator permissions. As a result, an authenticated user with no effective bucket or admin permissions can list remote replication target configuration for a bucket. Because the returned BucketTarget objects include remote target credentials, this can disclose replication access keys and secret keys. This vulnerability is fixed in 1.0.0-beta.9.

Vulnerability class: Information Disclosure

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (20.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-55188: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • Rustfs — versions >= 1.0.0-alpha.1, <= 1.0.0-beta.8

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-55188?
CVE-2026-55188 is a high-severity vulnerability in Rustfs, classified under Information Disclosure. CVSS score: 8.2/10. Published 2026-06-26.
How severe is CVE-2026-55188?
High severity. CVSS v3 base score is 8.2 out of 10.