CVE-2021-35535

CVE-2021-35535 is a high-severity vulnerability in Hitachienergy Relion 670 Firmware with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1188.

Key facts

Description

Insecure Boot Image vulnerability in Hitachi Energy Relion Relion 670/650/SAM600-IO series allows an attacker who manages to get access to the front network port and to cause a reboot sequences of the device may exploit the vulnerability, where there is a tiny time gap during the booting process where an older version of VxWorks is loaded prior to application firmware booting, could exploit the vulnerability in the older version of VxWorks and cause a denial-of-service on the product. This issue affects: Hitachi Energy Relion 670 Series 2.2.2 all revisions; 2.2.3 versions prior to 2.2.3.3. Hitachi Energy Relion 670/650 Series 2.2.0 all revisions; 2.2.4 all revisions. Hitachi Energy Relion 670/650/SAM600-IO 2.2.1 all revisions.

Frequently asked questions

What is CVE-2021-35535?
Insecure Boot Image vulnerability in Hitachi Energy Relion Relion 670/650/SAM600-IO series allows an attacker who manages to get access to the front network port and to cause a reboot sequences of the device may exploit the vulnerability, where there is a tiny time gap during the booting process where an older version of VxWorks is loaded prior to application firmware booting, could exploit the vulnerability in the older version of VxWorks and cause a denial-of-service on the product. This issue affects: Hitachi Energy Relion 670 Series 2.2.2 all revisions; 2.2.3 versions prior to 2.2.3.3. Hitachi Energy Relion 670/650 Series 2.2.0 all revisions; 2.2.4 all revisions. Hitachi Energy Relion 670/650/SAM600-IO 2.2.1 all revisions.
How severe is CVE-2021-35535?
CVE-2021-35535 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-35535 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35535?
CVE-2021-35535 primarily affects Hitachienergy Relion 670 Firmware. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-35535?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-35535 published?
CVE-2021-35535 was published on 2021-11-18 and last updated on 2026-06-17.

References

Affected products (9)

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