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.
Affected products
amazon: freertos-plus-tcp
References4
- aws.amazon.com/security/security-bulletins/2026-021-aws/ Vendor Advisory
- github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-… PatchVendor Advisory
- github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 Release Notes
- github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 Release Notes
Metrics
- CVSS 3.1
-
6.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 4.0
-
6.0
MEDIUM
Score source: CNA
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 13 · as of 13 November 2026
- CWE
- CWE-191
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