VulnerabilityModified

CVE-2026-1773

IEC 60870-5-104 used in RTU500: Potential Denial of Service impact on reception of invalid U-format frame.

HIGH 8.7EPSS 0.41%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

IEC 60870-5-104 used in RTU500: Potential Denial of Service impact on reception of invalid U-format frame. Product is only affected if IEC 60870-5-104 bi-directional functionality is configured. Enabling secure communication following IEC 62351-3 does not remediate the vulnerability but mitigates the risk of exploitation.

CVSS 4.0: 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.41% probability · 35th percentile
CISA KEV: Not listed
Weakness: CWE-184
Affected: hitachienergy/rtu540 firmware · hitachienergy/rtu560 firmware · hitachienergy/rtu520 firmware · hitachienergy/rtu530 firmware
Source: cybersecurity@hitachienergy.com

References

https://publisher.hitachienergy.com/preview?DocumentID=8DBD000237&LanguageCode=en&DocumentPartId=&Action=LaunchVendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.