CVE-2026-45039Public exploitNetwork attack vector

Peer impersonation via default RPC HMAC secret

Published May 28, 2026 · Updated May 28, 2026

Authentication bypass in RustFS before 1.0.0-beta.2 allows remote attackers to impersonate cluster peers through internode RPC. The get_shared_secret() function in crates/ecstore/src/rpc/http_auth.rs signs and verifies requests with the public rustfsadmin fallback when neither RUSTFS_RPC_SECRET nor the global S3 secret is configured. Network access to the RPC port in that fallback state permits accepted peer-signed calls to read or write disks, replicate data, and manipulate erasure groups beneath S3 authorization.

CVSS severity9.8
Critical
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in RustFS before 1.0.0-beta.2 allows remote attackers to impersonate cluster peers through internode RPC. The get_shared_secret() function in crates/ecstore/src/rpc/http_auth.rs signs and verifies requests with the public rustfsadmin fallback when neither RUSTFS_RPC_SECRET nor the global S3 secret is configured. Network access to the RPC port in that fallback state permits accepted peer-signed calls to read or write disks, replicate data, and manipulate erasure groups beneath S3 authorization.

The record

CVE
CVE-2026-45039
Published
May 28, 2026
Updated
May 28, 2026
Vendor
RustFS
Product
RustFS
Classifications
CWE-798, CWE-1392, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.0.0-beta.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

RustFS · RustFSversion=< 1.0.0-beta.2

Published CVSS scores

9.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
CWE-1392Use of Default Credentials
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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