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U BootApplication · Denx

CVE-2019-14194

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_read_reply when calling store_block in the NFSv2 case.

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_read_reply function performs an unbounded memcpy without proper length validation when calling store_block in NFSv2 read responses. This allows remote attackers to overwrite memory by sending maliciously crafted NFS packets, potentially achieving arbitrary code execution.

MitigationUpdate Das U-Boot to a version beyond 2019.07 that contains the patch for this vulnerability. If immediate updating is not feasible, disable NFS client support in the U-Boot configuration and ensure U-Boot is not exposed to untrusted NFS servers.

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 U-Boot version
    Run 'version' or 'ver' command in U-Boot shell, or inspect the U-Boot binary/bootlog for version string
    Affected if Version string shows 2019.07 or earlier (e.g., 2019.07, 2019.04, 2018.x, etc.)
  2. Verify NFS client support is enabled
    Check U-Boot configuration file (.config) for 'CONFIG_CMD_NFS' or 'CONFIG_NFS' setting, or run 'printenv' and look for NFS-related environment variables like 'nfsroot'
    Affected if CONFIG_CMD_NFS or CONFIG_NFS is set to 'y' in the build config, or NFS boot variables are defined in the environment
  3. Confirm NFS client is compiled into the binary
    Run 'help' in U-Boot shell and check if 'nfs' command is listed, or use 'grep -i nfs u-boot.bin' on the binary image
    Affected if The 'nfs' command is available in U-Boot or NFS-related strings are present in the binary
  4. Assess NFS exposure
    Review network configuration and boot scripts to determine if U-Boot is configured to mount from untrusted NFS servers
    Affected if U-Boot is configured to boot from or access NFS shares from network locations that are not trusted or are publicly accessible

You are affected if your U-Boot version is 2019.07 or earlier AND the NFS client feature (CONFIG_CMD_NFS) is enabled in your build configuration.

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 beyond 2019.07 that contains the patch for this vulnerability. If immediate updating is not feasible, disable NFS client support in the U-Boot configuration and ensure U-Boot is not exposed to untrusted NFS servers.

Recommended fix Moderate confidence

U-Boot 2019.10 or later stable release (the fix was committed shortly after the 2019.07 release)

  1. 1. Identify all embedded devices or systems running U-Boot version 2019.07 or earlier that use NFS client functionality
  2. 2. Obtain the latest stable U-Boot release from the official U-Boot repository (https://source.denx.de/u-boot/u-boot)
  3. 3. Rebuild U-Boot from source using the latest stable release that includes the fix for CVE-2019-14194
  4. 4. Verify the fix is present in the NFS code by checking that nfs_read_reply now includes proper bounds checking before calling store_block
  5. 5. Flash the updated U-Boot binary to affected devices
  6. 6. Test NFS client functionality to confirm the fix does not break legitimate NFS operations
  7. 7. If unable to upgrade immediately, disable NFS client support in U-Boot configuration (CONFIG_CMD_NFS) as a temporary mitigation
Caveat Upgrading U-Boot may introduce changes to board-specific configurations or driver support; review board-specific release notes and test thoroughly before deploying to production devices

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

Fix this in U Boot 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
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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-2019-14194 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