Vulnerability in Insyde InsydeH2O (CVE-2020-27339, CVSS 6.7)

Summary

Vulnerability in Insyde InsydeH2O (CVE-2020-27339). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

An issue was discovered in IdeBusDxe in Insyde InsydeH2O 5.x. Code in system management mode calls a function outside of SMRAM in response to a crafted software SMI, aka Inclusion of Functionality from an Untrusted Control Sphere. Modifying the well-known address of this function allows an attacker to gain control of the system with the privileges of system management mode.

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-2020-27339 has been found in Insyde InsydeH2O.
Successful exploitation can lead to full system takeover. CVSS score: 6.7/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Insyde InsydeH2O CVE-2020-27339" on the vendor's site.

CVE-2020-27339 (Insyde InsydeH2O) — CWE-20 / CVSS v3 6.7
Attack vector: local / 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-20) exists in Insyde InsydeH2O.

📍 Affected scope

Check the vendor advisory for the affected versions of Insyde InsydeH2O.

🔥 Severity

Severity: Medium (CVSS 6.7/10). Successful exploitation can lead to full system takeover.

🔧 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 Insyde InsydeH2O 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。

Summary

Original description

Auto-generated summary

Response actions

References