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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.

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




MEDIUM: 5.3CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

MEDIUM: 6.0CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/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/2026-021-aws/ vendor-advisory

github.com/...us-TCP/security/advisories/GHSA-7r59-2pgv-9v2r third-party-advisory

cve.org (CVE-2026-7423)

nvd.nist.gov (CVE-2026-7423)

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