# CVE-2023-30756: Null dereference in SIMATIC CP 1242-7 V2 (incl. SIPLUS variants)

> Remote attackers can cause denial of service in Siemens SIMATIC devices via a NULL dereference in the web server's Expect header handling.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:H/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Sep 2024
- **Updated:** 10 Sep 2024
- **Also known as:** GHSA-4p43-gfmp-qjmm

## What is CVE-2023-30756?

CVE-2023-30756 is a high-severity vulnerability in Siemens SIMATIC CP 1242-7 V2 (incl. SIPLUS variants), published on 10 Sep 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability has been identified in SIMATIC CP 1242-7 V2 (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-1 (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-1 DNP3 (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-1 IEC (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-7 LTE (All versions < V3.5.20), SIMATIC CP 1243-8 IRC (6GK7243-8RX30-0XE0) (All versions < V3.5.20), SIMATIC HMI Comfort Panels (incl. SIPLUS variants) (All versions), SIMATIC IPC DiagBase (All versions), SIMATIC IPC DiagMonitor (All versions), SIMATIC WinCC Runtime Advanced (All versions), SIPLUS TIM 1531 IRC (6AG1543-1MX00-7XE0) (All versions < V2.4.8), TIM 1531 IRC (6GK7543-1MX00-0XE0) (All versions < V2.4.8). The web server of the affected devices do not properly handle certain errors when using the Expect HTTP request header, resulting in NULL dereference.

This could allow a remote attacker with no privileges to cause a denial of service condition in the system.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-30756?


## How do I fix CVE-2023-30756?

No fix has been published for CVE-2023-30756 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-30756 being exploited?

There is no known exploitation of CVE-2023-30756 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-30756 and fix it if it is affected.

What it is: CVE-2023-30756 is a high-severity vulnerability in Siemens SIMATIC CP 1242-7 V2 (incl. SIPLUS variants), published on 10 Sep 2024. 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-2023-30756 in the wild and no public exploit code.

Affected product: Siemens SIMATIC CP 1242-7 V2 (incl. SIPLUS variants). 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-2023-30756/ (Markdown: https://insights.sbomify.com/CVE-2023-30756/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-30756
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-30756
- OSV: https://osv.dev/vulnerability/CVE-2023-30756

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From sbomify Insights: https://insights.sbomify.com/CVE-2023-30756/
Summaries are generated and may contain mistakes; the official description above is the record.