Buffer Overflow in SIMATIC HMI Comfort Outdoor Panels (CVE-2021-27386, CVSS 7.5)

Summary

Vulnerability in SIMATIC HMI Comfort Outdoor Panels (CVE-2021-27386). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels 7" & 15" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI Comfort Panels 4" - 22" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI KTP Mobile Panels KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V16 Update 4), SIMATIC WinCC Runtime Advanced (All versions < V16 Update 4). SmartVNC has a heap allocation leak vulnerability in the device layout handler on client side, which could result in a Denial-of-Service condition.

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-27386 has been found in SIMATIC HMI Comfort Outdoor Panels.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "SIMATIC HMI Comfort Outdoor Panels CVE-2021-27386" on the vendor's site.

CVE-2021-27386 (SIMATIC HMI Comfort Outdoor Panels) — CWE-119 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-119) exists in SIMATIC HMI Comfort Outdoor Panels.

📍 Affected scope

Check the vendor advisory for the affected versions of SIMATIC HMI Comfort Outdoor Panels.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで SIMATIC HMI Comfort Outdoor Panels を使っているサービスとバージョンを洗い出す。
2
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Buffer Overflow in SIMATIC HMI Comfort Outdoor Panels (CVE-2021-27386)

Summary

Original description

Auto-generated summary

Response actions

References