CVE-2026-7423
Integer Underflow in ICMP Echo Reply Processing in FreeRTOS-Plus-TCP
Description
Integer underflow in the ICMP and ICMPv6 echo reply handlers in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network user to cause a denial of service (device crash) when outgoing ping support is enabled, because header sizes are subtracted from a packet length field without validating the field is large enough, resulting in a heap out-of-bounds read of up to approximately 65KB. To mitigate this issue, users should upgrade to the fixed version when available.
INFO
Published Date :
April 29, 2026, 7:16 p.m.
Last Modified :
Oct. 26, 2026, 8:10 p.m.
Remotely Exploit :
No
Source :
ff89ba41-3aa1-4d27-914a-91399e9639e5
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 4.0 | MEDIUM | ff89ba41-3aa1-4d27-914a-91399e9639e5 |
Solution
- Upgrade FreeRTOS-Plus-TCP to V4.4.1 or later.
- Upgrade FreeRTOS-Plus-TCP to V4.2.6 or later.
- Ensure outgoing ping support is disabled.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-7423.
| URL | Resource |
|---|---|
| https://aws.amazon.com/security/security-bulletins/2026-021-aws/ | Vendor Advisory |
| https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 | Release Notes |
| https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 | Release Notes |
| https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-7r59-2pgv-9v2r | Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-7423 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-7423
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-7423 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-7423 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: FreeRTOS-Plus-TCP de AWS, Description: Desbordamiento negativo de enteros en los manejadores de respuesta de eco ICMP e ICMPv6 en FreeRTOS-Plus-TCP anterior a V4.4.1 y V4.2.6 permite a un usuario de red adyacente causar una denegación de servicio (caída del dispositivo) cuando el soporte de ping saliente está habilitado, porque los tamaños de las cabeceras se restan de un campo de longitud de paquete sin validar que el campo sea lo suficientemente grande, lo que resulta en una lectura fuera de límites de la pila (heap) de hasta aproximadamente 65KB. Para mitigar este problema, los usuarios deberían actualizar a la versión corregida cuando esté disponible. -
CVE Modified by ff89ba41-3aa1-4d27-914a-91399e9639e5
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'AWS', 'product': 'FreeRTOS-Plus-TCP', 'versions': [{'status': 'affected', 'version': '4.0.0', 'lessThan': '4.2.6', 'versionType': 'semver'}, {'status': 'affected', 'version': '4.3.0', 'lessThan': '4.4.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '4.2.6'}, {'status': 'unaffected', 'version': '4.4.1'}], 'collectionURL': 'https://github.com/FreeRTOS/FreeRTOS-Plus-TCP', 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-7423', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-04-29T19:08:03.742434Z'} -
Initial Analysis by [email protected]
May. 04, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:amazon:freertos-plus-tcp:*:*:*:*:*:*:*:* versions from (including) 4.0.0 up to (excluding) 4.2.6 *cpe:2.3:a:amazon:freertos-plus-tcp:*:*:*:*:*:*:*:* versions from (including) 4.3.0 up to (excluding) 4.4.1 Added Reference Type AMZN: https://aws.amazon.com/security/security-bulletins/2026-021-aws/ Types: Vendor Advisory Added Reference Type AMZN: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 Types: Release Notes Added Reference Type AMZN: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 Types: Release Notes Added Reference Type AMZN: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-7r59-2pgv-9v2r Types: Patch, Vendor Advisory -
New CVE Received by ff89ba41-3aa1-4d27-914a-91399e9639e5
Apr. 29, 2026
Action Type Old Value New Value Added Description Integer underflow in the ICMP and ICMPv6 echo reply handlers in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network user to cause a denial of service (device crash) when outgoing ping support is enabled, because header sizes are subtracted from a packet length field without validating the field is large enough, resulting in a heap out-of-bounds read of up to approximately 65KB. To mitigate this issue, users should upgrade to the fixed version when available. Added CVSS V4.0 AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/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 Added CVSS V3.1 AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-191 Added Reference https://aws.amazon.com/security/security-bulletins/2026-021-aws/ Added Reference https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 Added Reference https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 Added Reference https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-7r59-2pgv-9v2r