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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.

PUBLISHED Reserved 2026-04-29 | Published 2026-04-29 | Updated 2026-04-29 | Assigner AMZN




MEDIUM: 6.5CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

HIGH: 7.1CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-290: Authentication Bypass by Spoofing

Product status

Default status
unaffected

4.0.0 (semver) before 4.2.6
affected

4.3.0 (semver) before 4.4.1
affected

4.2.6
unaffected

4.4.1
unaffected

References

github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 patch

github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 patch

aws.amazon.com/security/security-bulletins/2026-021-aws/ vendor-advisory

github.com/...us-TCP/security/advisories/GHSA-jpw4-6h59-62w9 third-party-advisory

cve.org (CVE-2026-7422)

nvd.nist.gov (CVE-2026-7422)

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