# CVE-2023-50821: Denial of service in SIMATIC PCS 7 V9.1

> Attackers can cause persistent denial of service in Siemens SIMATIC PCS 7 and WinCC products by exploiting improper input validation in the login dialog.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **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:** 9 Apr 2024
- **Updated:** 26 Feb 2025
- **Also known as:** GHSA-m32q-g43c-p863

## What is CVE-2023-50821?

CVE-2023-50821 is a medium-severity denial of service vulnerability in Siemens SIMATIC PCS 7 V9.1, published on 9 Apr 2024. 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 PCS 7 V9.1 (All versions < V9.1 SP2 UC04), SIMATIC WinCC Runtime Professional V17 (All versions < V17 Update 8), SIMATIC WinCC Runtime Professional V18 (All versions < V18 Update 4), SIMATIC WinCC Runtime Professional V19 (All versions < V19 Update 1), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 16), SIMATIC WinCC V8.0 (All versions < V8.0 Update 5). The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service condition.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2023-50821?


## How do I fix CVE-2023-50821?

No fix has been published for CVE-2023-50821 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-50821 being exploited?

There is no known exploitation of CVE-2023-50821 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-50821 and fix it if it is affected.

What it is: CVE-2023-50821 is a medium-severity denial of service vulnerability in Siemens SIMATIC PCS 7 V9.1, published on 9 Apr 2024. 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-2023-50821 in the wild and no public exploit code.

Affected product: Siemens SIMATIC PCS 7 V9.1. 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-2023-50821/ (Markdown: https://insights.sbomify.com/CVE-2023-50821/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-50821
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-50821
- OSV: https://osv.dev/vulnerability/CVE-2023-50821

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From sbomify Insights: https://insights.sbomify.com/CVE-2023-50821/
Summaries are generated and may contain mistakes; the official description above is the record.