# CVE-2026-43171: EFI/CPER: don't dump the entire memory region

> A missing length check in the Linux kernel EFI/CPER handler allows an integer underflow, leading to memory disclosure or system crashes.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 6 May 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-43171, DEBIAN-CVE-2026-43171, GHSA-v6h5-rjwv-4cvj, ROOT-OS-DEBIAN-11-CVE-2026-43171, ROOT-OS-UBUNTU-2204-CVE-2026-43171, ROOT-OS-UBUNTU-2404-CVE-2026-43171, UBUNTU-CVE-2026-43171

## What is CVE-2026-43171?

CVE-2026-43171 is a medium-severity vulnerability in Linux kernel, published on 6 May 2026. 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:

EFI/CPER: don't dump the entire memory region

The current logic at cper_print_fw_err() doesn't check if the
error record length is big enough to handle offset. On a bad firmware,
if the ofset is above the actual record, length -= offset will
underflow, making it dump the entire memory.

The end result can be:

 - the logic taking a lot of time dumping large regions of memory;
 - data disclosure due to the memory dumps;
 - an OOPS, if it tries to dump an unmapped memory region.

Fix it by checking if the section length is too small before doing
a hex dump.

[ rjw: Subject tweaks ]

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-43171?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43171?

Apply the vendor's patch.

## Is CVE-2026-43171 being exploited?

There is no known exploitation of CVE-2026-43171 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-2026-43171 and fix it if it is affected.

What it is: CVE-2026-43171 is a medium-severity vulnerability in Linux kernel, published on 6 May 2026. 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-2026-43171 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-2026-43171/ (Markdown: https://insights.sbomify.com/CVE-2026-43171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43171
- OSV: https://osv.dev/vulnerability/CVE-2026-43171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43171/
Summaries are generated and may contain mistakes; the official description above is the record.