# CVE-2026-34961: barebox ext4 Extent Parsing Out-of-Bounds Read

> Attackers can trigger heap out-of-bounds reads in barebox via malicious ext4 images, potentially leaking memory or causing crashes during boot.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 May 2026
- **Updated:** 18 Jul 2026
- **Also known as:** GHSA-vv9w-vff6-5rx9

## What is CVE-2026-34961?

CVE-2026-34961 is a medium-severity memory corruption vulnerability in barebox, published on 11 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

barebox prior to version 2026.04.0 contains out-of-bounds read vulnerabilities in ext4 extent parsing due to missing validation of the eh_entries field against buffer capacity in fs/ext4/ext4_common.c. Attackers can supply a malicious ext4 filesystem image via USB, SD card, or network boot to trigger heap out-of-bounds reads during boot-time filesystem parsing, potentially redirecting reads to arbitrary disk offsets.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-34961?

It affects 1 product.


Products: Pengutronix Barebox.

## How do I fix CVE-2026-34961?

No fix has been published for CVE-2026-34961 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34961 being exploited?

There is no known exploitation of CVE-2026-34961 in the wild and no public exploit code.

## Other vulnerabilities in barebox

- [CVE-2019-15937](https://insights.sbomify.com/CVE-2019-15937/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-15938](https://insights.sbomify.com/CVE-2019-15938/): Memory corruption in n/a (critical 9.8)
- [CVE-2020-13910](https://insights.sbomify.com/CVE-2020-13910/): Information disclosure in n/a (critical 9.1)
- [CVE-2026-34963](https://insights.sbomify.com/CVE-2026-34963/): barebox EFI PE Loader Memory Safety Vulnerabilities (high 8.6)
- [CVE-2026-33243](https://insights.sbomify.com/CVE-2026-33243/): barebox: FIT Signature Verification Bypass Vulnerability (high 8.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34961 and fix it if it is affected.

What it is: CVE-2026-34961 is a medium-severity memory corruption vulnerability in barebox, published on 11 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-2026-34961 in the wild and no public exploit code.

Affected product: barebox. 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-2026-34961/ (Markdown: https://insights.sbomify.com/CVE-2026-34961/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34961
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34961
- OSV: https://osv.dev/vulnerability/CVE-2026-34961

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34961/
Summaries are generated and may contain mistakes; the official description above is the record.