# CVE-2026-8065: Auth bypass in RTU500 series CMU firmware

> Unauthenticated attackers can bypass authentication to upload arbitrary firmware on Hitachi Energy RTU500 devices, compromising device integrity and availability.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-gg49-9mrv-ff3f

## What is CVE-2026-8065?

CVE-2026-8065 is a critical authentication bypass vulnerability in Hitachi Energy RTU500 series CMU firmware, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-8065?


## How do I fix CVE-2026-8065?

No fix has been published for CVE-2026-8065 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-8065 being exploited?

There is no known exploitation of CVE-2026-8065 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-8065 PoC: Hitachi Energy RTU500 unauth firmware update bypass (CWE-306, CVSS 9.1). IoT/OT colored check + mass exploit — RTU500 fingerprint, firmware endpoint probe, lab-safe upload test. https://pocbit.org/pocs/cve-2026-8065 (github_poc): https://github.com/MRdark-ops/CVE-2026-8065
- CVE-2026-8065 PoC: Hitachi Energy RTU500 unauth firmware update bypass (CWE-306, CVSS 9.1). IoT/OT colored check + mass exploit — RTU500 fingerprint, firmware endpoint probe, lab-safe upload test. https://pocbit.org/pocs/cve-2026-8065 (github_poc): https://github.com/murrez/CVE-2026-8065

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8065 and fix it if it is affected.

What it is: CVE-2026-8065 is a critical authentication bypass vulnerability in Hitachi Energy RTU500 series CMU firmware, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-8065 in the wild and no public exploit code.

Affected product: Hitachi Energy RTU500 series CMU firmware. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-8065/ (Markdown: https://insights.sbomify.com/CVE-2026-8065/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8065
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8065
- OSV: https://osv.dev/vulnerability/CVE-2026-8065

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8065/
Summaries are generated and may contain mistakes; the official description above is the record.