CVE-2021-27424Network attack vector

Unauthenticated keypress disclosure via exposed MODBUS register

Published Mar 23, 2022 · Updated Apr 16, 2025

Information exposure in General Electric Multilin Universal Relay firmware before 8.1x allows remote attackers to read operator keypress data. The published MODBUS memory map exposes a last-key-pressed register that returns the most recent front-panel key input without authorization. Network access to a relay's MODBUS service is sufficient; the documented impact is limited to unauthorized information disclosure.

CVSS severity5.3
Medium
EPSS probability0.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information exposure in General Electric Multilin Universal Relay firmware before 8.1x allows remote attackers to read operator keypress data. The published MODBUS memory map exposes a last-key-pressed register that returns the most recent front-panel key input without authorization. Network access to a relay's MODBUS service is sufficient; the documented impact is limited to unauthorized information disclosure.

The record

CVE
CVE-2021-27424
Published
Mar 23, 2022
Updated
Apr 16, 2025
Vendor
General Electric
Product
Multilin Universal Relay Family
Classifications
CWE-200
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

5.3ICS-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

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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-200Information Exposure

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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