CVE-2021-35535

mediumpriority · track · 32OT risk · elevatedEPSS 0.007 · 52 %ileEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.67% (52nd) EPSS
CVSS 6.8 · medium
Is it mine?
32 products
Check your exposure
Who says so?
3 sources
cnnvd · enisa_euvd · cisa_csaf_ot

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

  • FixedRelion 650cisa_csaf_ot

    Update to 2.2.1.7 version or latest

  • FixedRelion 670cisa_csaf_ot

    Update to 2.2.1.7 version or latest

  • FixedSAM-IOcisa_csaf_ot

    Update to 2.2.1.7 version or latest

  • MitigationRelion 650cisa_csaf_ot

    Apply General Mitigation Factors

  • MitigationRelion 670cisa_csaf_ot

    Apply General Mitigation Factors

02

cvss

Technical severity, 0–10. One row per scoring source.

8.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–8.1

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4
v3.18.1highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.2 · impact 5.9
v3.18.1highCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · CISA US
v3.18.1highCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · ENISA EU
v3.18.1highCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · cybersecurity@hitachienergy.comexploitability 1.4 · impact 6
v3.17.4highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-1188USprimaryCWE-1188US
04

affected products (32)

Products and version ranges known to be affected.

showing 20 of 32
05

advisories (1)

Vendor and ecosystem advisories describing this.

  • ICSA-21-336-05Hitachi Energy Relion 670/650/SAM600-IO2021-11-04icsa · cisa_csaf_otUS

    Hitachi Energy is aware of a report from U.S. Department of Energy CyTRICS researcher of a vulnerability in the Relion 670/650/SAM600-IO series versions listed below. Recommended action for each affected version is listed in the Recommended Immediate Actions Section. 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.

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdcisa_csaf_otNVDCVE.orgMITRE
published 2021-11-18modified 2026-06-17
09

references (7)

External citations — patches, advisories, analysis.

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