# CVE-2026-34962: barebox ext4 Directory Parsing Infinite Loop Denial of Service

> Attackers can cause a boot hang in barebox by providing a malicious ext4 image with zero-length directory entries, requiring an upgrade to fix.

- **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-gh28-ww79-7h4v

## What is CVE-2026-34962?

CVE-2026-34962 is a medium-severity denial of service 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 version prior to 2026.04.0 contains a denial-of-service vulnerability in ext4 directory parsing in fs/ext4/ext4_common.c where the ext4fs_iterate_dir() function fails to validate that directory entry length values are non-zero. Attackers can supply a malicious ext4 filesystem image with a crafted directory entry containing a direntlen value of 0 to cause an infinite loop during directory listing or path resolution, resulting in the boot process hanging indefinitely.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2026-34962?

It affects 1 product.


Products: Pengutronix Barebox.

## How do I fix CVE-2026-34962?

No fix has been published for CVE-2026-34962 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34962 being exploited?

There is no known exploitation of CVE-2026-34962 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-2026-34962 and fix it if it is affected.

What it is: CVE-2026-34962 is a medium-severity denial of service 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-2026-34962 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-2026-34962/ (Markdown: https://insights.sbomify.com/CVE-2026-34962/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34962
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34962
- OSV: https://osv.dev/vulnerability/CVE-2026-34962

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34962/
Summaries are generated and may contain mistakes; the official description above is the record.