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Freertos Plus TcpApplication · Amazon

CVE-2026-7424

HIGH · 8.1 CVSS v3.1 Published 2026-04-29
Fix available
A fix is available. Upgrade to 4.2.6 / 4.4.1 or later.
See remediation →
86/100
Remediation priority · High
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
Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network actor to corrupt the device's IPv6 address assignment, DNS configuration, and lease times, and to cause a denial of service (permanent IP task freeze requiring hardware reset) by sending a single crafted DHCPv6 packet. The issue is present whenever DHCPv6 is enabled. To mitigate this issue, users should upgrade to version V4.2.6 or V4.4.1 or newer.

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

An integer underflow vulnerability exists in the DHCPv6 sub-option parser of FreeRTOS-Plus-TCP. An adjacent network attacker can send a single crafted DHCPv6 packet to trigger the underflow, corrupting IPv6 address assignment, DNS configuration, and lease times, or causing a permanent IP task freeze requiring hardware reset.

MitigationUpgrade FreeRTOS-Plus-TCP to version V4.2.6 or V4.4.1 or newer to patch the integer underflow in the DHCPv6 sub-option parser.

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
Freertos Plus TcpApplication
Affected:>= 4.0.0, < 4.2.6>= 4.3.0, < 4.4.1

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

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/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. Locate FreeRTOS-Plus-TCP version
    Search the codebase for the FreeRTOS-Plus-TCP version definition, typically found in a version header file such as version.h, FreeRTOSIPConfig.h, or a version-related header within the FreeRTOS-Plus-TCP directory
    Affected if The version cannot be determined or the code does not contain FreeRTOS-Plus-TCP
  2. Verify the installed version
    Extract the numeric version number (such as 4.0.0, 4.2.5, 4.3.0, or 4.4.0) and compare it against the affected ranges: 4.0.0 <= version < 4.2.6 OR 4.3.0 <= version < 4.4.1
    Affected if The version falls within any of the affected ranges listed
  3. Confirm DHCPv6 is enabled
    Inspect the network configuration files, typically FreeRTOSIPConfig.h or a similar configuration header, for the DHCPv6 setting (such as ipconfigUSE_DHCPV6 or similar) and verify it is set to enabled or 1
    Affected if DHCPv6 is enabled in the configuration
  4. Check for IPv6 usage
    Examine the network initialization code or configuration to determine if IPv6 networking is actively used or compiled into the firmware image
    Affected if IPv6/DHCPv6 functionality is present in the build

You are affected if your FreeRTOS-Plus-TCP version is 4.0.0 through 4.2.5, or 4.3.0 through 4.4.0, AND DHCPv6 is enabled in your 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 4.2.6 / 4.4.1 or later
Fixed in 4.2.64.4.1
Interim mitigation

Upgrade FreeRTOS-Plus-TCP to version V4.2.6 or V4.4.1 or newer to patch the integer underflow in the DHCPv6 sub-option parser.

Recommended fix High confidence

V4.2.6 or V4.4.1 (or newer)

  1. 1. Identify the current FreeRTOS Plus TCP version in use by checking the version header file or build configuration.
  2. 2. If using version >= 4.0.0 and < 4.2.6: upgrade to version V4.2.6 or later from the FreeRTOS-Plus-TCP GitHub releases.
  3. 3. If using version >= 4.3.0 and < 4.4.1: upgrade to version V4.4.1 or later from the FreeRTOS-Plus-TCP GitHub releases.
  4. 4. Rebuild the FreeRTOS firmware image with the updated library.
  5. 5. Redeploy the updated firmware to affected devices.
  6. 6. Verify DHCPv6 functionality is working correctly after the upgrade.

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

Fix this in Freertos Plus Tcp Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,060
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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-2026-7424 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