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Fencer Intel
high 7.5

CVE-2026-1773 json

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

published 8mo ago modified 4mo ago also EUVD-2026-8462

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

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.

Patch / fix

  • hitachienergy rtu540_firmware 13.7.8
  • hitachienergy rtu560_firmware 13.7.8
  • hitachienergy rtu520_firmware 13.7.8
  • hitachienergy rtu530_firmware 13.7.8

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-26-062-03 updated cvss 7.5

Hitachi Energy RTU500 Product (Update A)

  • Hitachi Energy RTU500 series CMU Firmware vers:RTU500_series_CMU_Firmware/>=12.7.1, <=12.7.7, vers:RTU500_series_CMU_Firmware/>=13.5.1, <=13.5.4, vers:RTU500_series_CMU_Firmware/>=13.6.1, <=13.6.2, vers:RTU500_series_CMU_Firmware/>=13.7.1, <=13.7.7
    affected: vendor fix, mitigation

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
8mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.7 CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Hitachi Energy RTU500 series CMU firmware

Classification

Weakness
  • CWE-184 Incomplete List of Disallowed Inputs

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.