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NuttxApplication · Apache

CVE-2020-17529

CRITICAL · 9.8 CVSS v3.1 Published 2020-12-09
Fix available
A fix is available. Upgrade to after 9.1.0 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
Out-of-bounds Write vulnerability in TCP Stack of Apache NuttX (incubating) versions up to and including 9.1.0 and 10.0.0 allows attacker to corrupt memory by supplying and invalid fragmentation offset value specified in the IP header. This is only impacts builds with both CONFIG_EXPERIMENTAL and CONFIG_NET_TCP_REASSEMBLY build flags enabled.

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

Out-of-bounds write vulnerability in Apache NuttX TCP reassembly logic allows memory corruption via crafted IP packets with invalid fragmentation offset values. Exploitation requires both CONFIG_EXPERIMENTAL and CONFIG_NET_TCP_REASSEMBLY build flags to be enabled, limiting attack surface to specific experimental builds.

MitigationDisable either CONFIG_EXPERIMENTAL or CONFIG_NET_TCP_REASSEMBLY build flags if unable to upgrade, or apply vendor patches to fix the bounds checking in the TCP reassembly code.

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
NuttxApplication
Affected:<= 9.1.0= 10.0.0

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

CVSS:3.1/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. Check if CONFIG_EXPERIMENTAL build flag is enabled
    Inspect your NuttX build configuration file (typically .config or defconfig) for the line CONFIG_EXPERIMENTAL=y
    Affected if CONFIG_EXPERIMENTAL is set to y (enabled)
  2. Check if CONFIG_NET_TCP_REASSEMBLY build flag is enabled
    Inspect your NuttX build configuration file for the line CONFIG_NET_TCP_REASSEMBLY=y
    Affected if CONFIG_NET_TCP_REASSEMBLY is set to y (enabled)
  3. Verify both required flags are simultaneously enabled
    Confirm that both CONFIG_EXPERIMENTAL=y and CONFIG_NET_TCP_REASSEMBLY=y exist in the same build configuration
    Affected if Both flags are enabled in the same build configuration (the vulnerability requires BOTH to be set)
  4. Identify the Apache NuttX version
    Check the NuttX version reported in your build system, firmware manifest, or version header file (nuttx/version.h or similar)
    Affected if Version is 9.1.0 or lower, or version is exactly 10.0.0

A system is affected if it runs a vulnerable NuttX version (9.1.0 or lower, or 10.0.0) AND has both CONFIG_EXPERIMENTAL and CONFIG_NET_TCP_REASSEMBLY build flags enabled simultaneously.

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 9.1.0
Interim mitigation

Disable either CONFIG_EXPERIMENTAL or CONFIG_NET_TCP_REASSEMBLY build flags if unable to upgrade, or apply vendor patches to fix the bounds checking in the TCP reassembly code.

Recommended fix High confidence

Apache NuttX 10.1.0 or later

  1. 1. Identify the current NuttX version in your build by checking the version header or build configuration
  2. 2. If running version 9.1.0 or earlier, or version 10.0.0, plan for an upgrade to version 10.1.0 or later
  3. 3. Obtain the latest stable NuttX release (10.1.0 or newer) from the official Apache NuttX repository at https://downloads.apache.org/nuttx/
  4. 4. Review the release notes for version 10.1.0 for any breaking changes that may affect your application
  5. 5. Update your build configuration to use the new version, ensuring all custom configurations are compatible
  6. 6. Rebuild your NuttX image with the new version
  7. 7. Test the application thoroughly to verify functionality remains intact after the upgrade
Caveat Review version 10.1.0 release notes for potential API changes or removed features

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

Fix this in Nuttx Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,380
Get the upgrade done

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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-2020-17529 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