CVE-2026-7424: FreeRTOS-Plus-TCP DHCPv6 Vulnerability Leads to DoS
The National Vulnerability Database has detailed CVE-2026-7424, a high-severity integer underflow vulnerability impacting FreeRTOS-Plus-TCP versions prior to V4.4.1 and V4.2.6. This flaw resides in the DHCPv6 sub-option parser and can be triggered by a single crafted DHCPv6 packet from an adjacent network actor.
Attackers can exploit this vulnerability to corrupt a device’s IPv6 address assignment, DNS configuration, and lease times. More critically, it can lead to a denial of service (DoS) by permanently freezing the IP task, necessitating a hardware reset. The National Vulnerability Database confirms this issue is present whenever DHCPv6 is enabled on affected FreeRTOS-Plus-TCP deployments.
Defenders must prioritize patching. The National Vulnerability Database advises upgrading to FreeRTOS-Plus-TCP version V4.2.6 or V4.4.1, or newer, to mitigate this risk. Given the ease of exploitation and the severe impact, this is not a vulnerability to defer.
What This Means For You
- If your organization utilizes FreeRTOS-Plus-TCP, particularly in IoT or embedded systems, you need to immediately identify all deployments running versions prior to V4.2.6 or V4.4.1. This isn't just a data integrity issue; it's a hard DoS that will take devices offline. Patching for CVE-2026-7424 is non-negotiable.
Related ATT&CK Techniques
🛡️ Detection Rules
2 rules · 6 SIEM formats2 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-7424: FreeRTOS-Plus-TCP DHCPv6 Integer Underflow DoS
title: CVE-2026-7424: FreeRTOS-Plus-TCP DHCPv6 Integer Underflow DoS
id: scw-2026-04-29-ai-1
status: experimental
level: critical
description: |
Detects the specific DHCPv6 traffic on UDP port 547 associated with the FreeRTOS-Plus-TCP vulnerability (CVE-2026-7424). An adjacent network actor sending a crafted DHCPv6 packet can trigger an integer underflow, leading to a denial of service by freezing the IP task. This rule specifically targets the DHCPv6 protocol on its standard port.
author: SCW Feed Engine (AI-generated)
date: 2026-04-29
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-7424/
tags:
- attack.initial_access
- attack.t1608.001
logsource:
category: dns
detection:
selection:
dst_port:
- 547
query|contains:
- 'DHCPv6'
EventType:
- 'network_event'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-7424 | DoS | FreeRTOS-Plus-TCP versions prior to V4.4.1 and V4.2.6 |
| CVE-2026-7424 | Information Disclosure | FreeRTOS-Plus-TCP versions prior to V4.4.1 and V4.2.6 |
| CVE-2026-7424 | Misconfiguration | DHCPv6 sub-option parser when DHCPv6 is enabled |
| CVE-2026-7424 | Memory Corruption | Integer underflow in DHCPv6 sub-option parser |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 29, 2026 at 22:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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