CVE-2021-27428Network attack vector

Unauthenticated firmware replacement via missing privilege enforcement

Published Mar 23, 2022 · Updated Apr 16, 2025

Unrestricted firmware upload in General Electric Multilin Universal Relay firmware before 8.10 allows remote attackers to replace device firmware. The EnerVista UR Setup path validates a firmware file's authenticity and integrity but does not enforce appropriate user privileges before the relay accepts the upgrade. Network reachability to the relay is sufficient because no authentication is required, and replacement firmware can alter protected device behavior or interrupt relay operation.

CVSS severity9.8
Critical
EPSS probability1.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted firmware upload in General Electric Multilin Universal Relay firmware before 8.10 allows remote attackers to replace device firmware. The EnerVista UR Setup path validates a firmware file's authenticity and integrity but does not enforce appropriate user privileges before the relay accepts the upgrade. Network reachability to the relay is sufficient because no authentication is required, and replacement firmware can alter protected device behavior or interrupt relay operation.

The record

CVE
CVE-2021-27428
Published
Mar 23, 2022
Updated
Apr 16, 2025
Vendor
General Electric
Product
Multilin Universal Relay Family
Classifications
CWE-434, T0857
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <8.1x

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

General Electric · Multilin Universal Relay Familyversion=unspecified <8.1x

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8ICS-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T0857System Firmware

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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