CVE-2021-22283Network attack vector

SCADA communication outage via unclosed MMS files

Published Feb 28, 2023 · Updated Mar 7, 2025

Improper initialization in ABB distribution-automation relays allows remote attackers with control-system access to stop SCADA communication. The integrated file system lets a crafted MMS client repeatedly open files without closing them until the file-handle limit activates an internal defense that blocks file-system access. Exploitation requires network access to the control system and leaves the relay in an internal fault state while SCADA and other protocol communications are inaccessible.

CVSS severity6.2
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in ABB distribution-automation relays allows remote attackers with control-system access to stop SCADA communication. The integrated file system lets a crafted MMS client repeatedly open files without closing them until the file-handle limit activates an internal defense that blocks file-system access. Exploitation requires network access to the control system and leaves the relay in an internal fault state while SCADA and other protocol communications are inaccessible.

The record

CVE
CVE-2021-22283
Published
Feb 28, 2023
Updated
Mar 7, 2025
Vendor
GENEREX SYSTEMS Computervertriebsgesellschaft mbH
Product
Relion 620 Series
Classifications
CWE-665, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 7, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=2.0.0 <2.0.11
  2. Affected versionversion=2.1.0 <2.1.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GENEREX SYSTEMS Computervertriebsgesellschaft mbH · Relion 620 Seriesversion=2.0.0 <2.0.11; version=2.1.0 <2.1.15
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · REC615version=1.0.0 <2.0.3
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · SMU615version=1.0.0 <1.0.2
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · REX640 PCL2version=1.1.0 <1.1.4
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · Relion 615 seriesversion=4.1.0 <4.1.8; version=4.1.0 <4.1.9; version=5.0.0 <5.0.12; version=5.1.0 <5.1.20
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · RER615version=2.0.0 <2.0.3
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · REX640 PCL3version=1.2.0 <1.2.1
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · Relion 611 seriesversion=1.0.0 <2.0.3
GENEREX SYSTEMS Computervertriebsgesellschaft mbH · REX640 PCL1version=1.0.0 <1.0.8

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.2ABBCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.9ABBCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:W/RC:C

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-665Improper Initialization
T0814Denial of Service

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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