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Vulnerabilities

Vulnerability · CVE-2026-1773

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

Published Feb 24, 2026 · catalog updated Jun 17, 2026 · rtu540 firmware

Check if you run it

No confirmed exploitation is on record for CVE-2026-1773. EPSS is 0.43%. Act only if a listed version of rtu540 firmware is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.43%
Remediation
Advisory link
Affected products
cpe hitachienergy/rtu520 firmware · cpe hitachienergy/rtu530 firmware · cpe hitachienergy/rtu540 firmware · cpe hitachienergy/rtu560 firmware

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe hitachienergy/rtu520 firmwareversion unspecified
  • cpe hitachienergy/rtu530 firmwareversion unspecified
  • cpe hitachienergy/rtu540 firmware13.8.1
  • cpe hitachienergy/rtu560 firmwareversion unspecified

How to fix CVE-2026-1773

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-1773. EPSS is 0.43%. Act only if a listed version of rtu540 firmware is installed.

Which versions are affected?

Compare what you have installed with hitachienergy/rtu540 firmware 13.8.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-184. EPSS 0.43%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 24, 2026 · NIST NVD

    Detected

    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.

  2. Jun 17, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2026-1773

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-1773

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-1773

    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 vulnerabil

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.