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CVE-2026-17539

MEDIUM 5.9 ALL-YEARS

Published 2026-09-03 · Last modified 2026-09-03 · Hitachi Energy · NVD: Awaiting Analysis

RTU500 has a vulnerability, where high-load scenarios, such as sending GI requests at short intervals, may cause a NULL pointer dereference in the last entry of the enhanced message queue. This can cause a BCI_IEC104 fatal write error, resulting in connection interruption and restart, and ultimately a denial of service for bidirectional IEC 60870-5-104 communication.

LIMITED SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 30th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

5.9CVSS 3.1 · MEDIUM · CNA

  • ConfidentialityNone
  • IntegrityNone
  • 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: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

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Affected

Vendors Hitachi Energy

Products Rtu500 Series Cmu Firmware

Weakness (CWE)

  • CWE-476: NULL pointer dereference

CVSS vector

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

References and research data (JSON)

All CVSS metrics

  • MEDIUM 5.9 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  • MEDIUM 5.9 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS