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CVE-2026-8065

CRITICAL 9.1

Published 2026-09-29 · Last modified 2026-09-29

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.

ELEVATED IMPACT

Severe if exploited (CVSS 9.1), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 42nd percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

9.1CVSS 3.1 · CRITICAL

  • ConfidentialityNone
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Hitachi Energy

Products Rtu500 Series Cmu Firmware

Weakness (CWE)

  • CWE-306: Missing authentication for critical function

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References and research data (JSON)

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

2 candidates
  • https://github.com/murrez/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

    PoC-in-GitHub · CVE-2026-8065
    PoC-in-GitHub · CVE-2026-8065 · Updated 2026-09-29T13:02:57Z
  • 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

    PoC-in-GitHub · CVE-2026-8065
    PoC-in-GitHub · CVE-2026-8065 · Updated 2026-09-29T19:02:13Z

All CVSS metrics

  • CRITICAL 9.1 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
  • CRITICAL 9.1 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS