CVE-2026-7423

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.

CVSS 4.0

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

CVSS 3.1

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

EPSS

0.2% chance of exploitation in the next 30 days; higher than 12% of CVEs (scores of 2026-10-26)

CWE

CWE-191

Published

2026-04-29

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• amazon:freertos-plus-tcp

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-7r59-2pgv-9v2r

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