CVE-2021-22779
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAuthentication Bypass by Spoofing vulnerability exists in EcoStruxure Control Expert (all versions prior to V15.0 SP1, including all versions of Unity Pro), EcoStruxure Control Expert V15.0 SP1, EcoStruxure Process Expert (all versions, including all versions of EcoStruxure Hybrid DCS), SCADAPack RemoteConnect for x70 (all versions), Modicon M580 CPU (all versions - part numbers BMEP* and BMEH*), Modicon M340 CPU (all versions - part numbers BMXP34*), that could cause unauthorized access in read and write mode to the controller by spoofing the Modbus communication between the engineering software and the controller.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceAuthentication bypass vulnerability in Schneider Electric's Modicon controllers and engineering software allows attackers to spoof Modbus communications between the engineering workstation and PLC, enabling unauthorized read/write access without any credentials. The attack exploits the lack of proper mutual authentication in the Modbus protocol used by EcoStruxure Control Expert, Process Expert, and SCADAPack RemoteConnect software when communicating with M580 and M340 CPUs.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 15.0= 15.0all versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify EcoStruxure Control Expert versionCheck the installed version of EcoStruxure Control Expert in the engineering workstation. This is typically viewable in the software's About or Help section, or by checking the installation directory for version metadata.Affected if Version is 15.0 or below (any version prior to V15.1)
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Identify EcoStruxure Process Expert installationDetermine if EcoStruxure Process Expert engineering software is installed on any workstation in the environment.Affected if The software is present (all versions are affected)
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Identify Remoteconnect software installationDetermine if Schneider Electric Remoteconnect software is installed on any workstation in the environment.Affected if The software is present (all versions are affected)
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Identify Modicon M580 controller firmware versionQuery the firmware version of Modicon M580 PLCs (models Bmep581020, Bmep581020h, Bmep582020, Bmep582020h, Bmep582040) connected to the network. This is typically done via the engineering software or by accessing the controller's web interface if available.Affected if Any of these M580 firmware versions are in use (all versions are affected)
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Assess network accessibility of Modbus trafficDetermine whether Modbus communications between engineering workstations and PLCs traverse network segments accessible to unauthorized parties, or if the network is properly segmented.Affected if Modbus traffic is accessible from untrusted network segments
A user is affected if they have EcoStruxure Control Expert version 15.0 or below, any version of EcoStruxure Process Expert or Remoteconnect, or any Modicon M580 firmware version from the listed models, especially when Modbus traffic is network-accessible.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped15.0
Upgrade to EcoStruxure Control Expert V15.1 or later (if available) and apply any available firmware updates for Modicon M580 and M340 controllers. Implement network segmentation to isolate OT systems from corporate networks and untrusted zones, and deploy firewalls or intrusion detection systems to monitor Modbus traffic for anomalous communication patterns.
EcoStruxure Control Expert V15.1 or later (contact Schneider for exact latest fixed release)
- 1. Navigate to the Schneider Electric download portal at download.schneider-electric.com
- 2. Locate EcoStruxure Control Expert (formerly Unity Pro)
- 3. Download version V15.1 or later (V15.0 SP1 is also affected according to the advisory, so ensure version is newer than SP1)
- 4. Install the upgrade following Schneider Electric's standard installation procedures
- 5. For Modicon M580 and M340 controllers, check for available firmware updates on the same portal or contact Schneider Electric support for remediation options
- 6. For RemoteConnect and Process Expert, contact Schneider Electric for specific patch guidance since these are listed as 'all versions' affected
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation16.0 h
- Implementation40.0 h
- Testing24.0 h
- Review / QA12.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $25,856.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-22779 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-22779 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data