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U BootApplication · Denx

CVE-2019-14202

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 a stack-based buffer overflow in this nfs_handler reply helper function: nfs_readlink_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 stack-based buffer overflow vulnerability exists in the nfs_readlink_reply function within the Das U-Boot NFS handler. The vulnerability is triggered when processing NFS readlink reply packets, allowing an attacker to overwrite stack memory by providing overly long data. With a CVSS 9.8 rating, this flaw is remotely exploitable without authentication and could lead to arbitrary code execution.

MitigationUpgrade Das U-Boot to a version newer than 2019.07. If upgrading is not immediately feasible, disable NFS boot functionality if not required, or implement network segmentation to limit exposure 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
    At the U-Boot prompt, run the 'version' command to display the installed U-Boot version and build information. If access to the U-Boot binary is available, strings or binwalk can also reveal version strings.
    Affected if The version displayed is 2019.07 or earlier (any version up to and including 2019.07).
  2. Verify NFS support is compiled in
    Check the U-Boot configuration file (such as .config) or the build output for the presence of CONFIG_NFS or similar NFS-related configuration options. If you have the U-Boot binary, use 'strings' or a disassembler to search for NFS-related function names like 'nfs_readlink_reply'.
    Affected if NFS support (CONFIG_NFS) is enabled in the build configuration.
  3. Check if NFS boot is configured
    Inspect the U-Boot environment variables for NFS-related settings. Look for variables such as 'bootargs' containing 'nfs://', or 'serverip' and 'rootpath' that point to an NFS share. Also check 'bootcmd' for NFS mount commands.
    Affected if The device is configured to boot from or mount an NFS share, indicated by NFS paths or server configurations in the boot environment.

You are affected if your U-Boot version is 2019.07 or earlier AND NFS support is compiled into the image AND the device is configured to use NFS functionality (boot from NFS or mount NFS shares).

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

Upgrade Das U-Boot to a version newer than 2019.07. If upgrading is not immediately feasible, disable NFS boot functionality if not required, or implement network segmentation to limit exposure to untrusted NFS servers.

Recommended fix High confidence

U-Boot 2019.10 or later stable release

  1. 1. Identify the specific U-Boot build configuration and target board in use
  2. 2. Obtain U-Boot source code from the official repository (https://source.denx.de/u-boot/u-boot.git)
  3. 3. Checkout the stable release 2019.10 or later (e.g., git checkout v2019.10)
  4. 4. Review board-specific configuration in configs/ directory and ensure configuration matches the target hardware
  5. 5. Cross-compile the U-Boot binary for the target architecture using the appropriate toolchain (e.g., make CROSS_COMPILE=<toolchain-prefix> <board>_defconfig)
  6. 6. Verify the build completes without errors
  7. 7. Back up the current U-Boot flash/image currently deployed on the target device
  8. 8. Flash the newly compiled U-Boot binary to the target device following the hardware-specific flashing procedure
Caveat Review the release notes between 2019.07 and 2019.10 for any changes that may affect board-specific configurations or NFS client behavior; some board defconfigs may have changed defaults

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
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2019-14202 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