Insufficient packet validation in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to bypass all checksum and minimum-size validation by spoofing the Ethernet source MAC address to match one of the device's own registered endpoints, because the loopback detection mechanism skips all input validation for packets whose source MAC matches a local endpoint.



To mitigate this issue, users should upgrade to the fixed version when available.

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
AWS FreeRTOS-Plus-TCP unaffected
Version Status Constraints
4.0.0 affected < 4.2.6
4.3.0 affected < 4.4.1
4.2.6 unaffected —
4.4.1 unaffected —

No data.

No data.

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Vendors Products
Amazon Subscribe
Freertos-plus-tcp Subscribe

Project Subscriptions

Vendors Products
Amazon Subscribe
Freertos-plus-tcp Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://aws.amazon.com/security/security-bulletins/2026-021-aws/ cve-icon cve-icon
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 cve-icon cve-icon
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 cve-icon cve-icon
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-jpw4-6h59-62w9 cve-icon cve-icon
History

Thu, 30 Apr 2026 08:30:00 +0000

Type Values Removed Values Added
First Time appeared Amazon
Amazon freertos-plus-tcp
Vendors & Products Amazon
Amazon freertos-plus-tcp

Wed, 29 Apr 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 29 Apr 2026 19:00:00 +0000

Type Values Removed Values Added
Description Insufficient packet validation in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to bypass all checksum and minimum-size validation by spoofing the Ethernet source MAC address to match one of the device's own registered endpoints, because the loopback detection mechanism skips all input validation for packets whose source MAC matches a local endpoint. To mitigate this issue, users should upgrade to the fixed version when available.
Title MAC Address Validation Bypass in FreeRTOS-Plus-TCP IPv4 and IPv6 Packet Processing
Weaknesses CWE-290
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: AMZN

Published:

Updated: 2026-04-29T19:07:31.899Z

Reserved: 2026-04-29T14:27:48.592Z

Link: CVE-2026-7422

cve-icon Vulnrichment

Updated: 2026-04-29T19:07:28.207Z

cve-icon NVD

Status : Received

Published: 2026-04-29T19:16:26.487

Modified: 2026-04-29T19:16:26.487

Link: CVE-2026-7422

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-30T08:15:31Z

Weaknesses