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Description

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 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.

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




HIGH: 8.1CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

HIGH: 7.2CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Problem types

CWE-191: Integer Underflow (Wrap or Wraparound)

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/2026-022-aws/ vendor-advisory

cve.org (CVE-2026-7424)

nvd.nist.gov (CVE-2026-7424)

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