# CVE-2021-42554: Memory corruption in n/a

> An SMM memory corruption flaw in InsydeH2O firmware allows attackers to write to SMRAM, potentially escalating privileges to System Management Mode.

- **Severity:** High 8.2 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Feb 2022
- **Updated:** 11 Aug 2026
- **Also known as:** GHSA-9hwg-wq94-95pr

## What is CVE-2021-42554?

CVE-2021-42554 is a high-severity memory corruption vulnerability in Insyde Insydeh2o, published on 3 Feb 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered in Insyde InsydeH2O with Kernel 5.0 before 05.08.42, Kernel 5.1 before 05.16.42, Kernel 5.2 before 05.26.42, Kernel 5.3 before 05.35.42, Kernel 5.4 before 05.42.51, and Kernel 5.5 before 05.50.51. An SMM memory corruption vulnerability in FvbServicesRuntimeDxe allows a possible attacker to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-42554?

It affects 16 products.


Products: Insyde Insydeh2o, Siemens Ruggedcom Ape1808 Firmware, Siemens Simatic Field Pg M5 Firmware, Siemens Simatic Field Pg M6 Firmware, Siemens Simatic Ipc127e Firmware, Siemens Simatic Ipc227g Firmware, Siemens Simatic Ipc277g Firmware, Siemens Simatic Ipc327g Firmware, Siemens Simatic Ipc377g Firmware, Siemens Simatic Ipc427e Firmware, Siemens Simatic Ipc477e Firmware, Siemens Simatic Ipc627e Firmware, Siemens Simatic Ipc647e Firmware, Siemens Simatic Ipc677e Firmware, Siemens Simatic Ipc847e Firmware, Siemens Simatic Itp1000 Firmware.

## How do I fix CVE-2021-42554?

No fix has been published for CVE-2021-42554 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42554 being exploited?

There is no known exploitation of CVE-2021-42554 in the wild and no public exploit code.

## Other vulnerabilities in Insyde Insydeh2o

- [CVE-2021-41842](https://insights.sbomify.com/CVE-2021-41842/): Missing authorization in n/a (critical 9.8)
- [CVE-2023-22612](https://insights.sbomify.com/CVE-2023-22612/): Memory corruption in n/a (high 8.8)
- [CVE-2023-22613](https://insights.sbomify.com/CVE-2023-22613/): Memory corruption in n/a (high 8.8)
- [CVE-2023-22614](https://insights.sbomify.com/CVE-2023-22614/): Memory corruption in n/a (high 8.8)
- [CVE-2023-22615](https://insights.sbomify.com/CVE-2023-22615/): Memory corruption in n/a (high 8.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42554 and fix it if it is affected.

What it is: CVE-2021-42554 is a high-severity memory corruption vulnerability in Insyde Insydeh2o, published on 3 Feb 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-42554 in the wild and no public exploit code.

Affected product: Insyde Insydeh2o. 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-2021-42554/ (Markdown: https://insights.sbomify.com/CVE-2021-42554/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42554
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42554
- OSV: https://osv.dev/vulnerability/CVE-2021-42554

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42554/
Summaries are generated and may contain mistakes; the official description above is the record.