Medium severity · published Sep 3, 2026
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…
5.9
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RS
RTU500 series CMU firmware · Hitachi Energy
12.7.1 through 12.7.7; 13.5.1 through 13.5.4; 13.6.1 through 13.6.3; 13.7.1 through 13.7.8; 13.8.1 through 13.8.2 · source: vendor
In the news
VulnerabilityHigh
Hitachi Energy RTU500 Product
View CSAF
Summary
Hitachi Energy is aware of vulnerabilities that affect RTU500 product versions listed in this document. These vulnerabilities if exploited can have impact on confidentiality, integrity and availability of the product. Please refer to the Recommended Immediate Actions for information about the mitigation/remediation.
The following versions of Hitachi Energy RTU500 Product are affected:
RTU500 series CMU Firmware vers:RTU500_series_CMU_Firmware/>=13.5.1|<=13.5.4, vers:RTU500_series_CMU_Firmware/>=13.6.1|<=13.6.3, vers:RTU500_series_CMU_Firmware/>=13.7.1|<=13.7.8, vers:RTU500_series_CMU_Firmware/>=13.8.1|<=13.8.2, vers:RTU500_series_CMU_Firmware/>=12.7.1|<=12.7.7 (CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6653)
CVSS
Vendor
Equipment
v3 8.8
Hitachi Energy
RTU500 series CMU Firmware
7 Vulnerabilities
NULL Pointer Dereference, ...
Oct 20, 2026·US-CERT ICS Advisories
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-17539
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-17539
publisher.hitachienergy.com
https://publisher.hitachienergy.com/preview?DocumentID=8DBD000259&LanguageCode=en&DocumentPartId=&Action=Launch
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