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 P
Hitachi Energy RTU500 series CMU firmware
CVSS
9.1CriticalExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.58%Chance of exploitation activity in the next 30 days, higher than 46% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
- 12.0RTU500 series CMU firmwareCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
Description
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.
Text from CVE List
Affected versions 1
- RTU500 series CMU firmwareaffected: 9.0 before 12.0CVE List