# CVE-2020-15795: Memory corruption in APOGEE PXC Compact (BACnet)

> A memory corruption vulnerability in Siemens building automation systems allows attackers to execute code or cause denial of service via malformed DNS responses.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Apr 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-cw98-4v34-2rc8

## What is CVE-2020-15795?

CVE-2020-15795 is a high-severity memory corruption vulnerability in Siemens APOGEE PXC Compact (BACnet), published on 22 Apr 2021. 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 APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus Source Code (Versions including affected DNS modules), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS domain name label parsing functionality does not properly validate the names in DNS-responses. The parsing of malformed responses could result in a write past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to execute code in the context of the current process or cause a denial-of-service condition.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2020-15795?

It affects 2 products.


Products: Siemens Nucleus Net, Siemens Nucleus Source Code.

## How do I fix CVE-2020-15795?

No fix has been published for CVE-2020-15795 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-15795 being exploited?

There is no known exploitation of CVE-2020-15795 in the wild and no public exploit code.

## Other vulnerabilities in Siemens APOGEE PXC Compact (BACnet)

- [CVE-2020-27009](https://insights.sbomify.com/CVE-2020-27009/): Memory corruption in APOGEE PXC Compact (BACnet) (high 8.1)
- [CVE-2020-27736](https://insights.sbomify.com/CVE-2020-27736/): Memory corruption in APOGEE PXC Compact (BACnet) (medium 6.5)
- [CVE-2020-27737](https://insights.sbomify.com/CVE-2020-27737/): Memory corruption in APOGEE PXC Compact (BACnet) (medium 6.5)
- [CVE-2020-27738](https://insights.sbomify.com/CVE-2020-27738/): Memory corruption in APOGEE PXC Compact (BACnet) (medium 6.5)
- [CVE-2021-25677](https://insights.sbomify.com/CVE-2021-25677/): Other in APOGEE PXC Compact (BACnet) (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-15795 and fix it if it is affected.

What it is: CVE-2020-15795 is a high-severity memory corruption vulnerability in Siemens APOGEE PXC Compact (BACnet), published on 22 Apr 2021. 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-2020-15795 in the wild and no public exploit code.

Affected product: Siemens APOGEE PXC Compact (BACnet). 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-2020-15795/ (Markdown: https://insights.sbomify.com/CVE-2020-15795/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-15795
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-15795
- OSV: https://osv.dev/vulnerability/CVE-2020-15795

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-15795/
Summaries are generated and may contain mistakes; the official description above is the record.