CVE-2021-27384
CRITICALEPSS 84th pctlDescription
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), 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). SmartVNC has an out-of-bounds memory access vulnerability in the device layout handler, represented by a binary data stream on client side, which can potentially result in code execution.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 84% of all known CVEs.
References
Related Vulnerabilities
Other CWE-788 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-9731 | High | 7.8 | 11% | - | - |
| CVE-2021-21105 | High | 8.8 | 5.9% | - | - |
| CVE-2021-21104 | High | 8.8 | 4.9% | - | - |
| CVE-2021-21082 | High | 7.8 | 4.5% | - | - |
| CVE-2019-8280 | Critical | 9.8 | 4.2% | - | Fix |
| CVE-2021-21093 | High | 7.8 | 3.9% | - | - |
Common questions
How do I fix CVE-2021-27384?
Published advisories record a fix for 10 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-27384 being actively exploited?
Not that we know of. CVE-2021-27384 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.6% is the estimated probability that it will be exploited in the next 30 days. That is higher than 84% of all scored CVEs.
How severe is CVE-2021-27384?
CVE-2021-27384 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-27384 affect?
Published advisories record a fix for simatic hmi comfort outdoor panels 15\" firmware (NVD), simatic hmi comfort outdoor panels 7\" firmware (NVD), simatic hmi comfort panels 22\" firmware (NVD), simatic hmi comfort panels 4\" firmware (NVD), and 6 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-27384
Markdown
[](https://tridentstack.com/cve/CVE-2021-27384)HTML
<a href="https://tridentstack.com/cve/CVE-2021-27384"><img src="https://tridentstack.com/cve/badge/CVE-2021-27384.svg" alt="CVE-2021-27384"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-02.