Unauthenticated firmware upload in Hitachi RTU500 (OT/ICS) enables device takeover and potential disruption of critical infrastructure (energy/transport), warranting broad alerting.
CVE-2026-8065
Unauthenticated firmware upload in Hitachi RTU500 enables device takeover
Is CVE-2026-8065 being exploited?
Not confirmed. CVE-2026-8065 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-8065?
CVE-2026-8065 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-8065?
Not known from our data. No patch reference has been recorded for CVE-2026-8065, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-8065 affect?
CVE-2026-8065 affects Hitachi Energy RTU500 (end-of-life firmware versions). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-8065?
Isolate affected RTUs, apply vendor mitigations, replace EOL units, monitor logs
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated POST to firmware endpoint allows arbitrary firmware upload → full device compromise, remote code execution, integrity loss, and service disruption.
Immediate action required
- affected>= 9.0 and < 12.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.