Cyber Resilience

CVE-2026-7424

Memory Safety in Amazon Freertos-Plus-Tcp 4.0.0 – 4.2.6

Published
29 April 2026
Modified
04 May 2026
Patch / advisory
CVSS Score v4 7.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0022 13th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-7424 is a high-severity Wrap or Wraparound (CWE-191) vulnerability in Amazon Freertos-Plus-Tcp. Its CVSS base score is 7.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-7424 is an integer underflow vulnerability (CWE-191) in the DHCPv6 sub-option parser within FreeRTOS-Plus-TCP versions before V4.4.1 and V4.2.6. It affects embedded devices or systems using this TCP/IP stack when DHCPv6 is enabled, as the flaw exists whenever that feature is active. Published on 2026-04-29, it carries a CVSS v3.1 base score of 8.1 (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H), highlighting high impacts on integrity and availability with no confidentiality effects.

An adjacent network actor can exploit this vulnerability by sending a single crafted DHCPv6 packet, requiring low attack complexity and no privileges or user interaction. Successful exploitation allows the attacker to corrupt the device's IPv6 address assignment, DNS configuration, and lease times, while also triggering a denial of service through a permanent IP task freeze that necessitates a hardware reset.

Mitigation requires upgrading to FreeRTOS-Plus-TCP V4.2.6, V4.4.1, or newer versions, as stated in the official advisories. Relevant resources include the AWS security bulletin at https://aws.amazon.com/security/security-bulletins/2026-022-aws/, GitHub release tags for V4.2.6 and V4.4.1, and the security advisory at https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-wrhm-c99p-2p8g.

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-7423Same product: Amazon Freertos-Plus-Tcp
CVE-2026-7425Same product: Amazon Freertos-Plus-Tcp
CVE-2026-7426Same product: Amazon Freertos-Plus-Tcp
CVE-2024-38373Same product: Amazon Freertos-Plus-Tcp
CVE-2025-11617Same product: Amazon Freertos-Plus-Tcp
CVE-2025-11616Same product: Amazon Freertos-Plus-Tcp
CVE-2025-11618Same product: Amazon Freertos-Plus-Tcp
CVE-2026-7422Same product: Amazon Freertos-Plus-Tcp
CVE-2023-23933Same vendor: Amazon
CVE-2026-5747Same vendor: Amazon

Affected Assets

amazon
freertos-plus-tcp
4.0.0 — 4.2.6 · 4.3.0 — 4.4.1

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and static/dynamic analysis directly find integer underflow defects before code is released.

Security engineering principles require use of safe arithmetic constructs or language features that structurally eliminate integer underflow during subtraction.

Input validation can reject or sanitize values that would cause a subtraction to underflow the representable range.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 full match
prevents

Secure SDLC practices directly prevent integer underflow defects via input validation, bounds checking, and static analysis.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis can surface underflow flaws after they are introduced.

PR.PS-02 partial match
prevents

Routine patching can remediate known underflow bugs once they are discovered in deployed software.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development catches integer underflow defects before release.

prevents

Secure development lifecycle mandates input validation and arithmetic checks that prevent integer underflow.

prevents

Application security requirements include bounds checking and safe arithmetic to avoid underflow conditions.

prevents

Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.

prevents

Secure coding standards directly prescribe safe integer handling and overflow/underflow prevention.

References