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U BootApplication · Denx

CVE-2019-14196

CRITICAL · 9.8 CVSS v3.0 Published 2019-07-31
Fix available
A fix is available. Upgrade to after 2019.07 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
An issue was discovered in Das U-Boot through 2019.07. There is an unbounded memcpy with a failed length check at nfs_lookup_reply.

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

A buffer overflow vulnerability exists in Das U-Boot's NFS client implementation where the nfs_lookup_reply handler performs an unbounded memcpy() without proper length validation. The failed length check allows an attacker controlling a malicious NFS server to overflow the heap or stack buffer, potentially achieving remote code execution on the affected device during the network boot process.

MitigationUpdate Das U-Boot to a version after 2019.07 that contains the fix for proper bounds checking. If updating is not feasible, disable NFS boot functionality and ensure network boot interfaces are not exposed to untrusted networks.

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
U BootApplication
Affected:<= 2019.07

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/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. Identify if Das U-Boot is the bootloader
    Examine the device or system boot logs, console output, or firmware to confirm Das U-Boot is running as the bootloader. Look for the U-Boot prompt or version string during boot.
    Affected if Das U-Boot is confirmed as the bootloader and the version cannot be determined or is <= 2019.07
  2. Determine the installed U-Boot version
    Access the U-Boot console or boot logs and run the 'version' or 'printenv' command to retrieve the U-Boot version number. Compare this version against the affected range.
    Affected if The U-Boot version is <= 2019.07 or cannot be determined
  3. Check if NFS client support is enabled
    Inspect the U-Boot configuration (CONFIG_CMD_NFS or similar NFS-related config options in the build configuration or defconfig file) to see if NFS client functionality was compiled into the image.
    Affected if NFS client support is enabled in the U-Boot build configuration
  4. Verify if NFS boot is configured
    Examine U-Boot environment variables (via 'printenv' in the U-Boot console) for NFS-related boot variables such as 'netboot', 'nfsroot', 'bootfile' or boot commands that invoke NFS mount operations.
    Affected if NFS boot variables or NFS mount commands are present in the U-Boot environment
  5. Determine exposure of network boot interfaces
    Review network configuration and firewall rules to assess whether the device network boot interfaces (used for PXE or NFS boot) are accessible from untrusted networks or the internet.
    Affected if Network boot interfaces are exposed to untrusted or public networks

The environment is affected if Das U-Boot version is <= 2019.07 AND NFS client support is enabled AND NFS boot is configured or the device uses network boot with potential exposure to malicious NFS servers.

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 a release after 2019.07
Interim mitigation

Update Das U-Boot to a version after 2019.07 that contains the fix for proper bounds checking. If updating is not feasible, disable NFS boot functionality and ensure network boot interfaces are not exposed to untrusted networks.

Recommended fix High confidence

U-Boot 2019.10 or later

  1. 1. Identify the current U-Boot version in use by checking the version during boot or in the build configuration
  2. 2. Obtain a fixed U-Boot release (2019.10 or later) from the official U-Boot repository at https://source.denx.de/u-boot/u-boot/-/releases
  3. 3. Build the new U-Boot image for your specific target platform using the standard build process (make CROSS_COMPILE=<toolchain> <board>_defconfig && make CROSS_COMPILE=<toolchain>)
  4. 4. Replace the vulnerable U-Boot binary/image on the target device using the appropriate flashing mechanism for your hardware
  5. 5. Verify the new version by checking the U-Boot banner during boot
Caveat Minor: Verify board-specific configuration and device tree settings are compatible with the newer release, as board defconfigs may have changed

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

Fix this in U Boot Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,120
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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-2019-14196 in production — separate from our analysis above.

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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