# CVE-2024-8935: Auth bypass in Modicon M340 CPU (part numbers BMXP34*)

> Man-in-the-middle attacks can bypass authentication in Schneider Electric PLCs, causing denial of service and data compromise.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 13 Nov 2024
- **Updated:** 13 Nov 2024
- **Also known as:** GHSA-6rch-pvx5-r93q

## What is CVE-2024-8935?

CVE-2024-8935 is a high-severity authentication bypass vulnerability in Schneider Electric Modicon M340 CPU (part numbers BMXP34*), published on 13 Nov 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

CWE-290: Authentication Bypass by Spoofing vulnerability exists that could cause a denial of service and loss
of confidentiality and integrity of controllers when conducting a Man-In-The-Middle attack between the
controller and the engineering workstation while a valid user is establishing a communication session. This
vulnerability is inherent to Diffie Hellman algorithm which does not protect against Man-In-The-Middle attacks.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2024-8935?


## How do I fix CVE-2024-8935?

No fix has been published for CVE-2024-8935 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-8935 being exploited?

There is no known exploitation of CVE-2024-8935 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-8935 and fix it if it is affected.

What it is: CVE-2024-8935 is a high-severity authentication bypass vulnerability in Schneider Electric Modicon M340 CPU (part numbers BMXP34*), published on 13 Nov 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2024-8935 in the wild and no public exploit code.

Affected product: Schneider Electric Modicon M340 CPU (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-2024-8935/ (Markdown: https://insights.sbomify.com/CVE-2024-8935/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-8935
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-8935
- OSV: https://osv.dev/vulnerability/CVE-2024-8935

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From sbomify Insights: https://insights.sbomify.com/CVE-2024-8935/
Summaries are generated and may contain mistakes; the official description above is the record.