# CVE-2026-54429: Denial of service in SIMATIC S7-PLCSIM Advanced

> An unauthenticated local attacker can cause a denial-of-service condition in SIMATIC S7-PLCSIM Advanced by exhausting memory with high-volume multicast traffic.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-xhg3-q2f6-w8cg

## What is CVE-2026-54429?

CVE-2026-54429 is a medium-severity denial of service vulnerability in Siemens SIMATIC S7-PLCSIM Advanced, published on 14 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability has been identified in SIMATIC S7-PLCSIM Advanced (All versions). Affected devices do not properly handle high-volume multicast network traffic, which can exhaust available memory resources in the affected application. This could allow an unauthenticated attacker on the local network segment to cause a denial-of-service condition of the affected application. The affected application becomes inaccessible and requires a manual restart; no project data is lost. Successful exploitation requires a specific project configuration to be already active on the targeted instance.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-54429?


## How do I fix CVE-2026-54429?

No fix has been published for CVE-2026-54429 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54429 being exploited?

There is no known exploitation of CVE-2026-54429 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54429 and fix it if it is affected.

What it is: CVE-2026-54429 is a medium-severity denial of service vulnerability in Siemens SIMATIC S7-PLCSIM Advanced, published on 14 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-54429 in the wild and no public exploit code.

Affected product: Siemens SIMATIC S7-PLCSIM Advanced. 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-2026-54429/ (Markdown: https://insights.sbomify.com/CVE-2026-54429/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54429
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54429
- OSV: https://osv.dev/vulnerability/CVE-2026-54429

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-54429/
Summaries are generated and may contain mistakes; the official description above is the record.