What’s Vulnerable › Vulnerabilities

CVE-2026-7422: MAC Address Validation Bypass in FreeRTOS-Plus-TCP IPv4 and IPv6 Packet Processing

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-29 · updated 2026-10-26
• Weakness: CWE-290

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.

Affected products

• AWS FreeRTOS-Plus-TCP: from 4.0.0 before 4.2.6; from 4.3.0 before 4.4.1 — fixed in 4.2.6, 4.4.1

How to fix

Upgrade to a fixed version: AWS FreeRTOS-Plus-TCP 4.2.6, 4.4.1. Check the vendor advisory for mitigations.

References

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

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