CVE-2021-22786Network attack vector

Unauthenticated controller-memory disclosure

Published Feb 1, 2023 · Updated Feb 5, 2025

Information exposure in Schneider Electric Modicon PAC controllers allows remote attackers to read sensitive controller-memory data over Modbus TCP. Schneider Electric has not disclosed the specific request, response field, or bounds-checking error that causes controller memory to enter a Modbus TCP reply. Exploitation requires network access to the controller's Modbus TCP service and affects confidentiality only; no data alteration or service interruption is reported.

CVSS severity7.5
High
EPSS probability0.63%
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 Schneider Electric Modicon PAC controllers allows remote attackers to read sensitive controller-memory data over Modbus TCP. Schneider Electric has not disclosed the specific request, response field, or bounds-checking error that causes controller memory to enter a Modbus TCP reply. Exploitation requires network access to the controller's Modbus TCP service and affects confidentiality only; no data alteration or service interruption is reported.

The record

CVE
CVE-2021-22786
Published
Feb 1, 2023
Updated
Feb 5, 2025
Vendor
Distributed Data Systems
Product
Modicon M580 Safety CPU
Classifications
CWE-200, T0866
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 5, 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=All Versions

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Distributed Data Systems · Modicon M580 Safety CPUversion=All Versions
Distributed Data Systems · Modicon M580 CPUversion=All <V3.20
Distributed Data Systems · Modicon Momentum Unity M1E Processorversion=All <V2.3
Distributed Data Systems · Modicon Quantumversion=All Versions
Distributed Data Systems · Modicon MC80version=All <V1.6
Distributed Data Systems · Modicon M340 CPUversion=All <V3.30

Published CVSS scores

7.5Schneider ElectricCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.

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-200Exposure of Sensitive Information to an Unauthorized Actor
T0866Exploitation of Remote Services

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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