# CVE-2020-7565: Weak cryptography in Modicon M221, all references, all versions

> An attacker can break encryption keys by capturing traffic between EcoStruxure software and Modicon M221 controllers, compromising data confidentiality.

- **Severity:** High 7.1 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Nov 2020
- **Updated:** 29 May 2026
- **Also known as:** GHSA-93f9-wg2h-r6p5

## What is CVE-2020-7565?

CVE-2020-7565 is a high-severity vulnerability in Modicon M221, all references, all versions, published on 19 Nov 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A CWE-326: Inadequate Encryption Strength vulnerability exists in Modicon M221 (all references, all versions) that could allow the attacker to break the encryption key when the attacker has captured the traffic between EcoStruxure Machine - Basic software and Modicon M221 controller.

Weakness: CWE-326 (Inadequate Encryption Strength)

## Which versions are affected by CVE-2020-7565?

It affects 1 product.


Products: Schneider-Electric Modicon M221 Firmware.

## How do I fix CVE-2020-7565?

No fix has been published for CVE-2020-7565 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-7565 being exploited?

There is no known exploitation of CVE-2020-7565 in the wild and no public exploit code.

## Other vulnerabilities in Modicon M221, all references, all versions

- [CVE-2020-28214](https://insights.sbomify.com/CVE-2020-28214/): Weak cryptography in Modicon M221 (all references, all versions) (critical 9.8)
- [CVE-2018-7790](https://insights.sbomify.com/CVE-2018-7790/): Auth bypass in Modicon M221, all references, all versions prior to firmware V1.6.2.0 (critical 9.8)
- [CVE-2018-7791](https://insights.sbomify.com/CVE-2018-7791/): Auth bypass in Modicon M221, all references, all versions prior to firmware V1.6.2.0 (critical 9.8)
- [CVE-2018-7821](https://insights.sbomify.com/CVE-2018-7821/): Denial of service in SoMachine Basic and Modicon M221, SoMachine Basic, all versions Modicon M221, all references, all versions prior to firmware V1.10.0.0 (high 7.5)
- [CVE-2018-7792](https://insights.sbomify.com/CVE-2018-7792/): Weak cryptography in Modicon M221, all references, all versions prior to firmware V1.6.2.0 (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-7565 and fix it if it is affected.

What it is: CVE-2020-7565 is a high-severity vulnerability in Modicon M221, all references, all versions, published on 19 Nov 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-7565 in the wild and no public exploit code.

Affected product: Modicon M221, all references, all versions. 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-2020-7565/ (Markdown: https://insights.sbomify.com/CVE-2020-7565/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-7565
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-7565
- OSV: https://osv.dev/vulnerability/CVE-2020-7565

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-7565/
Summaries are generated and may contain mistakes; the official description above is the record.