CVE-2026-8066

Published Sep 29, 2026 CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed
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.

Analysis

AI-generated

Technical impact

A directory traversal flaw (CWE‑23) in the firmware of Hitachi Energy RTU500 series devices lets an unauthenticated attacker write arbitrary files to the system. By overwriting configuration or executable files, an attacker could modify device data or disrupt operation, disabling critical functions.

Affected Systems

The vulnerability affects Hitachi Energy RTU500 series RTU firmware that has reached end‑of‑life. No specific version numbers are provided; any device running the affected firmware is potentially compromised.

Risk and Exploitability

The CVSS score of 9.1 indicates high severity, and the EPSS score of 1% suggests that exploitation is plausible, although not extremely common. The vulnerability is not listed in the CISA KEV catalog, but its impact and ease of exploitation make it a significant risk. An attacker would likely exploit the weakness by sending a crafted upload request that triggers the directory traversal, uploading a file that implements malicious logic or alters configuration. Because no authentication is required, anyone with network access to the device could carry out the attack.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the latest firmware update provided by Hitachi Energy for RTU500 series devices.
  • Disable the file upload capability or restrict it to trusted network segments.
  • Implement file integrity monitoring and alerting for unauthorized modifications.
  • Ensure network segmentation isolates RTU devices from untrusted traffic.

Generated by OpenCVE AI on September 30, 2026 at 04:31 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Directory Traversal Allowing Arbitrary File Write in Hitachi Energy RTU500 Firmware
Type Values Removed Values Added
Title Directory Traversal Allowing Arbitrary File Write in Hitachi Energy RTU500 Firmware
Type Values Removed Values Added
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.
Weaknesses CWE-23
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'}

Subscriptions

No data.

Weaknesses
  • CWE-23

    Relative Path Traversal

Sources

Status
PUBLISHED
Assigner
Hitachi Energy
Published
Updated
Sep 29, 2026, 3:52 PM
Reserved
May 7, 2026, 5:51 AM
Status
Awaiting Analysis
Published
Sep 29, 2026, 10:17 AM
Modified
Sep 29, 2026, 9:39 PM