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BareboxApplication · Pengutronix

CVE-2026-34962

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-11
Fix available
A fix is available. Upgrade to 2026.04.0 or later.
See remediation →
57/100
Remediation priority · Elevated
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 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.

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 versions prior to 2026.04.0 have a denial-of-service vulnerability in ext4fs_iterate_dir() where directory entry length (direntlen) is not validated before use. A malicious ext4 filesystem image with direntlen=0 causes an infinite loop during directory iteration, hanging the boot process indefinitely.

MitigationUpgrade barebox to version 2026.04.0 or later which includes validation for non-zero directory entry lengths. If upgrading is not possible, ensure only trusted ext4 filesystem images are used during boot.

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
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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. Identify if barebox is in use
    Locate the barebox binary or bootloader installation on the system. Check for barebox-related files in /boot, /usr/share/barebox, or the firmware/boot partition.
    Affected if barebox is installed and used as the bootloader
  2. Determine the installed barebox version
    Run 'barebox --version' or check version information in the barebox binary/boot image. Compare the version number to 2026.04.0.
    Affected if The barebox version is earlier than 2026.04.0 (e.g., 2025.x.x or earlier)
  3. Check if ext4 filesystem support is enabled
    Inspect the barebox configuration (barebox.cfg, .config, or build configuration) for CONFIG_EXT4FS=y or ext4fs support being compiled in. Alternatively, run 'barebox -l' or check available commands for ext4fs-related commands.
    Affected if ext4 filesystem support is compiled into or enabled in barebox
  4. Verify if ext4 filesystems are loaded during boot
    Review boot scripts, environment variables, or boot configuration files used by barebox to identify if ext4 filesystems are being mounted or accessed (e.g., 'ext4load' commands, mount operations on ext4 partitions).
    Affected if The boot process loads or mounts ext4 filesystem images

You are affected if barebox versions prior to 2026.04.0 are in use AND ext4 filesystem support is enabled AND ext4 filesystems are loaded during boot, as this combination allows the malicious image to trigger the infinite loop.

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

Upgrade barebox to version 2026.04.0 or later which includes validation for non-zero directory entry lengths. If upgrading is not possible, ensure only trusted ext4 filesystem images are used during boot.

Recommended fix Moderate confidence

2026.04.0

  1. Obtain barebox version 2026.04.0 or later from the official barebox repository
  2. Build the new barebox version following the standard build process for your target platform
  3. Update the barebox binary on the affected system with the newly built version
  4. Verify the update by testing ext4 filesystem mounting and directory listing functionality

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

Fix this in Barebox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

Scan for this in your stack

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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-2026-34962 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