# CVE-2020-15798: Auth bypass in SIMATIC HMI Comfort Panels (incl. SIPLUS variants)

> Remote attackers can gain full device access via unauthenticated Telnet service on affected Siemens HMI panels and SINAMICS drives.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 9 Feb 2021
- **Updated:** 2 Jun 2026
- **Also known as:** GHSA-p3v5-8v5r-qgp2

## What is CVE-2020-15798?

CVE-2020-15798 is a critical authentication bypass vulnerability in Siemens SIMATIC HMI Comfort Panels (incl. SIPLUS variants), published on 9 Feb 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 SIMATIC HMI Comfort Panels (incl. SIPLUS variants) (All versions < V16 Update 3a), SIMATIC HMI KTP Mobile Panels (All versions < V16 Update 3a), SINAMICS GH150 (All versions), SINAMICS GL150 (with option X30) (All versions), SINAMICS GM150 (with option X30) (All versions), SINAMICS SH150 (All versions), SINAMICS SL150 (All versions), SINAMICS SM120 (All versions), SINAMICS SM150 (All versions), SINAMICS SM150i (All versions). Affected devices with enabled telnet service do not require authentication for this service. This could allow a remote attacker to gain full access to the device. (ZDI-CAN-12046)

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2020-15798?

It affects 10 products.


Products: Siemens Simatic Hmi Comfort Panels Firmware, Siemens Simatic Hmi Ktp Mobile Panels Firmware, Siemens Sinamics Gh150 Firmware, Siemens Sinamics Gl150 Firmware, Siemens Sinamics Gm150 Firmware, Siemens Sinamics Sh150 Firmware, Siemens Sinamics Sl150 Firmware, Siemens Sinamics Sm120 Firmware, Siemens Sinamics Sm150 Firmware, Siemens Sinamics Sm150i Firmware.

## How do I fix CVE-2020-15798?

No fix has been published for CVE-2020-15798 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-15798 being exploited?

There is no known exploitation of CVE-2020-15798 in the wild and no public exploit code.

## Other vulnerabilities in Siemens SIMATIC HMI Comfort Panels (incl. SIPLUS variants)

- [CVE-2022-40227](https://insights.sbomify.com/CVE-2022-40227/): Denial of service in SIMATIC HMI Comfort Panels (incl. SIPLUS variants) (high 7.5)
- [CVE-2019-19276](https://insights.sbomify.com/CVE-2019-19276/): Denial of service in SIMATIC HMI Comfort Panels 1st Generation (incl. SIPLUS variants) (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-15798 and fix it if it is affected.

What it is: CVE-2020-15798 is a critical authentication bypass vulnerability in Siemens SIMATIC HMI Comfort Panels (incl. SIPLUS variants), published on 9 Feb 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-2020-15798 in the wild and no public exploit code.

Affected product: Siemens SIMATIC HMI Comfort Panels (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-2020-15798/ (Markdown: https://insights.sbomify.com/CVE-2020-15798/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-15798
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-15798
- OSV: https://osv.dev/vulnerability/CVE-2020-15798

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-15798/
Summaries are generated and may contain mistakes; the official description above is the record.