# CVE-2023-27336: Softing edgeConnector Siemens OPC UA Server Null Pointer Dereference Denial-of-Service Vulnerability

> Remote attackers can cause a denial-of-service condition in Softing edgeConnector Siemens by exploiting a null pointer dereference in certificate handling without authentication.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 May 2024
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-v94g-ggp4-7f34

## What is CVE-2023-27336?

CVE-2023-27336 is a high-severity vulnerability in Softing edgeConnector Siemens, published on 3 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Softing edgeConnector Siemens OPC UA Server Null Pointer Dereference Denial-of-Service Vulnerability. This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Softing edgeConnector Siemens. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the handling of OPC client certificates. The issue results from dereferencing a NULL pointer. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-20508.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-27336?

It affects 3 products.


Products: Softing Edgeaggregator, Softing Edgeconnector, Softing Secure Integration Server.

## How do I fix CVE-2023-27336?

No fix has been published for CVE-2023-27336 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-27336 being exploited?

There is no known exploitation of CVE-2023-27336 in the wild and no public exploit code.

## Other vulnerabilities in Softing edgeConnector Siemens

- [CVE-2022-2336](https://insights.sbomify.com/CVE-2022-2336/): Softing Secure Integration Server Improper Authentication (critical 9.8)
- [CVE-2023-27335](https://insights.sbomify.com/CVE-2023-27335/): Softing edgeAggregator Client Cross-Site Scripting Remote Code Execution Vulnerability (high 8.8)
- [CVE-2024-0860](https://insights.sbomify.com/CVE-2024-0860/): Cleartext Transmission of Sensitive Information in Softing edgeConnector and edgeAggregator (high 8.0)
- [CVE-2023-27334](https://insights.sbomify.com/CVE-2023-27334/): Softing edgeConnector Siemens ConditionRefresh Resource Exhaustion Denial-of-Service Vulnerability (high 7.5)
- [CVE-2023-38125](https://insights.sbomify.com/CVE-2023-38125/): Softing edgeAggregator Permissive Cross-domain Policy with Untrusted Domains Remote Code Execution Vulnerability (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-27336 and fix it if it is affected.

What it is: CVE-2023-27336 is a high-severity vulnerability in Softing edgeConnector Siemens, published on 3 May 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-2023-27336 in the wild and no public exploit code.

Affected product: Softing edgeConnector Siemens. 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-2023-27336/ (Markdown: https://insights.sbomify.com/CVE-2023-27336/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-27336
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-27336
- OSV: https://osv.dev/vulnerability/CVE-2023-27336

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-27336/
Summaries are generated and may contain mistakes; the official description above is the record.