# CVE-2026-34963: barebox EFI PE Loader Memory Safety Vulnerabilities

> An attacker can achieve code execution in the bootloader context by supplying a malicious EFI PE binary that triggers a heap buffer overflow via integer overflow.

- **Severity:** High 8.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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-qj4w-p892-c352

## What is CVE-2026-34963?

CVE-2026-34963 is a high-severity 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 multiple memory-safety vulnerabilities in the EFI PE loader in efi/loader/pe.c where integer overflow in virtual image size computation using 32-bit arithmetic on section VirtualAddress and size values allows undersized heap allocation, and PE section loading logic fails to validate that PointerToRawData plus copied size remains within the PE file buffer. An attacker can supply a malicious EFI PE binary via TFTP, USB, SD card, or network boot to trigger heap buffer overflow or out-of-bounds read from heap memory, potentially achieving code execution in bootloader context.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-34963?

It affects 1 product.


Products: Pengutronix Barebox.

## How do I fix CVE-2026-34963?

No fix has been published for CVE-2026-34963 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34963 being exploited?

There is no known exploitation of CVE-2026-34963 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-2026-33243](https://insights.sbomify.com/CVE-2026-33243/): barebox: FIT Signature Verification Bypass Vulnerability (high 8.3)
- [CVE-2021-37847](https://insights.sbomify.com/CVE-2021-37847/): Information disclosure in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34963 and fix it if it is affected.

What it is: CVE-2026-34963 is a high-severity 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-2026-34963 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-2026-34963/ (Markdown: https://insights.sbomify.com/CVE-2026-34963/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34963
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34963
- OSV: https://osv.dev/vulnerability/CVE-2026-34963

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34963/
Summaries are generated and may contain mistakes; the official description above is the record.