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BareboxApplication · Pengutronix

CVE-2026-34963

HIGH · 7.8 CVSS v3.1 Published 2026-05-11
Fix available
A fix is available. Upgrade to 2026.04.0 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

barebox bootloader versions prior to 2026.04.0 contain two memory-safety flaws in the EFI PE loader (efi/loader/pe.c). First, 32-bit integer overflow in virtual image size calculation using VirtualAddress and size fields results in undersized heap allocations. Second, the PE section loading logic lacks validation that PointerToRawData plus the size to copy stays within the PE file buffer bounds. An attacker can supply a specially crafted EFI PE binary via TFTP, USB, SD card, or network boot to trigger heap buffer overflows or out-of-bounds reads, potentially achieving code execution in bootloader context.

MitigationUpdate barebox to version 2026.04.0 or later which includes proper 64-bit arithmetic for size calculations and bounds validation in the PE loader. If updating is not immediately feasible, restrict boot sources (TFTP, USB, SD, network) to trusted binaries only.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
BareboxApplication
Affected:< 2026.04.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed barebox version
    Run the 'bareboxversion' command at the bootloader prompt, or inspect boot logs and build artifacts for the barebox version string
    Affected if The version is prior to 2026.04.0 (e.g., 2025.x.x or earlier)
  2. Check if EFI PE loader is in use
    Inspect boot configuration and environment variables for EFI boot paths or PE binary loading directives (look for .efi file references in boot commands)
    Affected if EFI PE binaries are being loaded via boot commands such as bootefi, efiboot, or similar
  3. Identify configured boot sources
    Review boot scripts and environment for enabled boot mechanisms: check for tftp, usb, mmc/sd, or network boot (dhcp, pxelinux) configuration
    Affected if Any of TFTP, USB, SD card, or network boot interfaces are enabled and point to potentially untrusted sources
  4. Verify source authentication
    Examine whether boot sources (TFTP server, USB device, SD card, network) are from trusted and controlled sources only, or are publicly accessible
    Affected if Boot media or network boot sources allow loading binaries from untrusted or unauthenticated origins

You are affected if your barebox version is earlier than 2026.04.0 AND the EFI PE loader is actively used to boot from TFTP, USB, SD card, or network sources that are not exclusively trusted.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2026.04.0 or later
Fixed in 2026.04.0
Interim mitigation

Update barebox to version 2026.04.0 or later which includes proper 64-bit arithmetic for size calculations and bounds validation in the PE loader. If updating is not immediately feasible, restrict boot sources (TFTP, USB, SD, network) to trusted binaries only.

Recommended fix Moderate confidence

Barebox 2026.04.0 or later

  1. 1. Identify all deployed Barebox instances that may load EFI PE binaries from untrusted sources (TFTP, USB, SD cards, network boot)
  2. 2. Obtain Barebox version 2026.04.0 or later from the official barebox repository at https://www.barebox.org/ or https://github.com/barebox/barebox
  3. 3. Build the updated Barebox for your target platform(s) using the standard build process (typically 'make ARCH=<arch> defconfig' followed by 'make ARCH=<arch>')
  4. 4. Replace the vulnerable Barebox bootloader image on affected devices with the fixed version
  5. 5. Verify the upgrade by checking the Barebox version at boot time using the 'version' command
  6. 6. Ensure that any EFI PE binaries loaded from network or removable media are from trusted sources, as a defense-in-depth measure
Caveat Ensure your target board's defconfig is compatible with the 2026.04.0 release; verify any custom board-specific patches apply cleanly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Barebox Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34963 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data