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CVE-2021-27426: GE UR IED firmware versions prior to version 8.1x with “Basic” security variant does not allow the disabling o

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CRITICAL 9.8REMOTEUPGRADEUPGRADEUPGRADE

CVE-2021-27426 is a critical-severity flaw (CVSS 9.8) affecting multilin b30 firmware, multilin b90 firmware, multilin c60 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

GE UR IED firmware versions prior to version 8.1x with “Basic” security variant does not allow the disabling of the “Factory Mode,” which is used for servicing the IED by a “Factory” user.

Why this priority

  • Critical severity
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score9.8 (Critical)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance1.2% (top 32%)
CISA exploited listNo
WeaknessCWE-453
Published2022-03-23
Last modified2026-06-17
Publisher (CNA): ICS-CERT · Vendor: ge

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Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

ge multilin b30 firmware UPGRADE
Affected: < 8.10
Fixed in: 8.10
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
ge multilin b90 firmware UPGRADE
Affected: < 8.10
Fixed in: 8.10
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
ge multilin c60 firmware UPGRADE
Affected: < 8.10
Fixed in: 8.10
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
ge multilin c70 firmware UPGRADE
Affected: < 8.10
Fixed in: 8.10
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
ge multilin c95 firmware UPGRADE
Affected: < 8.10
Fixed in: 8.10
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
ge multilin d30 firmware UPGRADE
Affected: < 8.10
Fixed in: 8.10
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-27426?

multilin b30 firmware: upgrade to 8.10; multilin b90 firmware: upgrade to 8.10; multilin c60 firmware: upgrade to 8.10. Exact commands for each OS are on this page.

Is CVE-2021-27426 being exploited?

CVE-2021-27426 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-27426 affect?

CVE-2021-27426 affects multilin b30 firmware, multilin b90 firmware, multilin c60 firmware. Severity is critical (CVSS 9.8). GE UR IED firmware versions prior to version 8.1x with “Basic” security variant does not allow the disabling of the “Factory Mode,” which is used for servicing the IED by a “Factory” user.

How urgent is CVE-2021-27426?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

References

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