CVE-2021-27196: Improper Input Validation vulnerability in Hitachi ABB Power Grids Relion 670 Series, Relion 670/650 Series, Relion 670/650/SAM600-IO, Relion 650, REB500, RTU50

Improper Input Validation vulnerability in Hitachi ABB Power Grids Relion 670 Series, Relion 670/650 Series, Relion 670/650/SAM600-IO, Relion 650, REB500, RTU50

Improper Input Validation vulnerability in Hitachi ABB Power Grids Relion 670 Series, Relion 670/650 Series, Relion 670/650/SAM600-IO, Relion 650, REB500, RTU500 Series, FOX615 (TEGO1), MSM, GMS600, PWC600 allows an attacker with access to the IEC 61850 network with knowledge of how to reproduce the attack, as well as the IP addresses of the different IEC 61850 access points (of IEDs/products), to force the device to reboot, which renders the device inoperable for approximately 60 seconds. This vulnerability affects only products with IEC 61850 interfaces. This issue affects: Hitachi ABB Power Grids Relion 670 Series 1.1; 1.2.3 versions prior to 1.2.3.20; 2.0 versions prior to 2.0.0.13; 2.1; 2.2.2 versions prior to 2.2.2.3; 2.2.3 versions prior to 2.2.3.2. Hitachi ABB Power Grids Relion 670/650 Series 2.2.0 versions prior to 2.2.0.13. Hitachi ABB Power Grids Relion 670/650/SAM600-IO 2.2.1 versions prior to 2.2.1.6. Hitachi ABB Power Grids Relion 650 1.1; 1.2; 1.3 versions prior to 1.3.0.7. Hitachi ABB Power Grids REB500 7.3; 7.4; 7.5; 7.6; 8.2; 8.3. Hitachi ABB Power Grids RTU500 Series 7.x version 7.x and prior versions; 8.x version 8.x and prior versions; 9.x version 9.x and prio

Description from the National Vulnerability Database, published by MITRE

What it means for a small business

If your business uses Relion 670 Firmware, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 1.6%, higher than 75% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

Weekly security brief

The flaws that hit local websites, every Friday.

One short email: what got exploited this week, which WordPress plugins broke, and what to check. Unsubscribe in one click.