# CVE-2021-22779: Auth bypass 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*)

> Attackers can spoof Modbus communications to gain unauthorized read and write access to Schneider Electric industrial controllers.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2021
- **Updated:** 29 May 2026
- **Also known as:** GHSA-qx3c-87pm-wqpc

## What is CVE-2021-22779?

CVE-2021-22779 is a medium-severity authentication bypass vulnerability 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*), published on 14 Jul 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Authentication 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.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2021-22779?

It affects 32 products.


Products: Schneider-Electric Ecostruxure Control Expert, Schneider-Electric Ecostruxure Process Expert, Schneider-Electric Modicon M340 Bmxp341000 Firmware, Schneider-Electric Modicon M340 Bmxp342010 Firmware, Schneider-Electric Modicon M340 Bmxp342020 Firmware, Schneider-Electric Modicon M340 Bmxp342030 Firmware, Schneider-Electric Modicon M580 Bmeh582040 Firmware, Schneider-Electric Modicon M580 Bmeh582040c Firmware, Schneider-Electric Modicon M580 Bmeh582040s Firmware, Schneider-Electric Modicon M580 Bmeh584040 Firmware, Schneider-Electric Modicon M580 Bmeh584040c Firmware, Schneider-Electric Modicon M580 Bmeh584040s Firmware, Schneider-Electric Modicon M580 Bmeh586040 Firmware, Schneider-Electric Modicon M580 Bmeh586040c Firmware, Schneider-Electric Modicon M580 Bmeh586040s Firmware, Schneider-Electric Modicon M580 Bmep581020 Firmware, Schneider-Electric Modicon M580 Bmep581020h Firmware, Schneider-Electric Modicon M580 Bmep582020 Firmware, Schneider-Electric Modicon M580 Bmep582020h Firmware, Schneider-Electric Modicon M580 Bmep582040 Firmware and 12 more.

## How do I fix CVE-2021-22779?

No fix has been published for CVE-2021-22779 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-22779 being exploited?

There is no known exploitation of CVE-2021-22779 in the wild and no public exploit code.

## Other vulnerabilities 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*)

- [CVE-2022-37300](https://insights.sbomify.com/CVE-2022-37300/): Auth bypass in EcoStruxure Control Expert (critical 9.8)
- [CVE-2020-28212](https://insights.sbomify.com/CVE-2020-28212/): Auth bypass in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) (critical 9.8)
- [CVE-2020-7475](https://insights.sbomify.com/CVE-2020-7475/): Code injection in EcoStruxure Control Expert (all versions prior to 14.1 Hot Fix), Unity Pro (all versions), Modicon M340 (all versions prior to V3.20), Modicon M580 (all versions prior to V3.10) (critical 9.8)
- [CVE-2023-27976](https://insights.sbomify.com/CVE-2023-27976/): Other in EcoStruxure Control Expert (high 8.8)
- [CVE-2020-28213](https://insights.sbomify.com/CVE-2020-28213/): Code injection in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-22779 and fix it if it is affected.

What it is: CVE-2021-22779 is a medium-severity authentication bypass vulnerability 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*), published on 14 Jul 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-22779 in the wild and no public exploit code.

Affected product: 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*). No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-22779/ (Markdown: https://insights.sbomify.com/CVE-2021-22779/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22779
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22779
- OSV: https://osv.dev/vulnerability/CVE-2021-22779

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-22779/
Summaries are generated and may contain mistakes; the official description above is the record.