CVE-2026-3869Network attack vector

Unauthenticated PLC compromise via flawed authentication algorithm

Published Sep 11, 2026 · Updated Sep 11, 2026

Authentication bypass in Schneider Electric Modicon M580 and Modicon M580 Safety controllers allows remote attackers to compromise the PLC. Schneider Electric has not published which authentication routine or algorithm operation incorrectly accepts the unauthenticated connection. Exposure requires an M580 application level before 4.00 or M580 Safety application level before 4.20 and grants access that can disclose or alter data or interrupt the PLC.

CVSS severity9.2
Critical
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in Schneider Electric Modicon M580 and Modicon M580 Safety controllers allows remote attackers to compromise the PLC. Schneider Electric has not published which authentication routine or algorithm operation incorrectly accepts the unauthenticated connection. Exposure requires an M580 application level before 4.00 or M580 Safety application level before 4.20 and grants access that can disclose or alter data or interrupt the PLC.

The record

CVE
CVE-2026-3869
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
Distributed Data Systems
Product
Modicon M580 Safety CPU
Classifications
CWE-303, T0866
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record 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=All versions with an application level below 4.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Distributed Data Systems · Modicon M580 Safety CPUversion=All versions with an application level below 4.20
Distributed Data Systems · Modicon M580 CPUversion=All versions with an application level below 4.00

Published CVSS scores

9.2Schneider ElectricCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8Schneider ElectricCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-303Incorrect Implementation of Authentication Algorithm
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo