What is CVE-2026-8065?

CVE-2026-8065 is a critical-severity vulnerability in Hitachi Energy Rtu500 Series Cmu Firmware, classified under Missing Authentication for Critical Function. CVSS score: 9.1/10. Published 2026-09-29.

How severe is CVE-2026-8065?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Auth bypass in Hitachi Energy Rtu500 Series Cmu Firmware

CVE-2026-8065

An authentication bypass vulnerability in the firmware update endpoint of Hitachi Energy RTU500 end-of-life versions allows an unauthenticated attacker to upload arbitrary firmware through a crafted POST request. Successful exploitation could allow the attacker to modify device functionality or compromise the integrity or availability of the device.

Vulnerability class: Broken Authentication

Published 2026-09-29 · last modified 2026-09-29.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Hitachi Energy Rtu500 Series Cmu Firmware

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

publisher.hitachienergy.com/preview

Frequently asked questions

What is CVE-2026-8065?: CVE-2026-8065 is a critical-severity vulnerability in Hitachi Energy Rtu500 Series Cmu Firmware, classified under Missing Authentication for Critical Function. CVSS score: 9.1/10. Published 2026-09-29.
How severe is CVE-2026-8065?: Critical severity. CVSS v3 base score is 9.1 out of 10.