# CVE-2021-47138: cxgb4: avoid accessing registers when clearing filters

> A flaw in the cxgb4 driver allows out-of-bound memory access when clearing filters during hardware errors, potentially causing a system crash.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Mar 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2021-47138, GHSA-qjmm-w6cw-3hf3, UBUNTU-CVE-2021-47138

## What is CVE-2021-47138?

CVE-2021-47138 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

cxgb4: avoid accessing registers when clearing filters

Hardware register having the server TID base can contain
invalid values when adapter is in bad state (for example,
due to AER fatal error). Reading these invalid values in the
register can lead to out-of-bound memory access. So, fix
by using the saved server TID base when clearing filters.

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

## Which versions are affected by CVE-2021-47138?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47138?

Apply the vendor's patch.

## Is CVE-2021-47138 being exploited?

There is no known exploitation of CVE-2021-47138 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47138 and fix it if it is affected.

What it is: CVE-2021-47138 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 2024. 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-2021-47138 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2021-47138/ (Markdown: https://insights.sbomify.com/CVE-2021-47138/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47138
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47138
- OSV: https://osv.dev/vulnerability/CVE-2021-47138

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47138/
Summaries are generated and may contain mistakes; the official description above is the record.