CVE-2026-8066: Hitachi Energy RTU500 series CMU firmware · Relative Path Traversal
Affects Hitachi Energy RTU500 series CMU firmwareSource CVE Database V5
Not known to be exploited · CVSS 9.1 Critical : upgrade to 12.0 as a priority.
Data as of 12 Nov 2026, 23:25 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 12.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade Hitachi Energy RTU500 series CMU firmware to 12.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Hitachi EnergyRTU500 series CMU firmware | Affected
| Fixed in
|
Description
A directory traversal vulnerability in the file upload functionality of Hitachi Energy RTU500 end-of-life versions allows an unauthenticated attacker to write or overwrite arbitrary files on the device file system. Depending on the files affected, successful exploitation could result in unauthorized modification of device data or disruption of the device’s intended operation.