What is CVE-2026-17539?

CVE-2026-17539 is a medium-severity vulnerability, classified under NULL Pointer Dereference. CVSS score: 5.9/10. Published 2026-09-03.

How severe is CVE-2026-17539?

Medium severity. CVSS v3 base score is 5.9 out of 10.

CVE-2026-17539

CVE-2026-17539

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.

EPSS: 0.004 (28.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

cybersecurity@hitachienergy.com

Frequently asked questions

What is CVE-2026-17539?: CVE-2026-17539 is a medium-severity vulnerability, classified under NULL Pointer Dereference. CVSS score: 5.9/10. Published 2026-09-03.
How severe is CVE-2026-17539?: Medium severity. CVSS v3 base score is 5.9 out of 10.