CVE-2026-8065Network attack vector

Unauthenticated firmware upload via update endpoint bypass

Published Sep 29, 2026 · Updated Sep 29, 2026

Authentication bypass in Hitachi Energy RTU500 Series CMU Firmware allows remote attackers to upload arbitrary firmware via crafted POST requests. The firmware update endpoint accepts an upload without enforcing authentication; no public vendor record identifies the handler or failed check. Exploitation requires network access to that endpoint and can alter device functionality or interrupt operation, but the precise downstream effect is not published.

CVSS severityUnavailable
Unscored
EPSS probability0.58%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Hitachi Energy RTU500 Series CMU Firmware allows remote attackers to upload arbitrary firmware via crafted POST requests. The firmware update endpoint accepts an upload without enforcing authentication; no public vendor record identifies the handler or failed check. Exploitation requires network access to that endpoint and can alter device functionality or interrupt operation, but the precise downstream effect is not published.

The record

CVE
CVE-2026-8065
Published
Sep 29, 2026
Updated
Sep 29, 2026
Vendor
Hitachi Energy
Product
RTU500 Series CMU Firmware
Classifications
T1601
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 29, 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=9.0 <12.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Hitachi Energy · RTU500 Series CMU Firmwareversion=9.0 <12.0

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1601Modify System Image

Public exploit references

No public exploit references are available in this record.

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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