CVE-2026-8066
Critical
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.
SeverityCritical
CVSS9.1
Exploit probability—
ProductRTU500 series CMU firmware
PublishedSep 29, 2026
First seenSep 29, 2026
Weakness typeCWE-23CWE-23
How to fix
Update
- Hitachi Energy RTU500 series CMU firmware12.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Hitachi Energy RTU500 series CMU firmware | 9.0 ≤ v < 12.0 | 12.0 |
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