Vulnerability · Published Oct 16, 2026 · Assigned by AMZN

CVE-2026-109588Numeric truncation in the MPU buffer authorization check in FreeRTOS-Kernel

High 8.8

In plain English

A high-severity out-of-bounds write in FreeRTOS-Kernel from FreeRTOS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).

Severity (CVSS 3.1)8.8High

Exploit odds (30 days)0.2%top 95.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Numeric truncation of the buffer length in the MPU buffer authorization check in FreeRTOS-Kernel V11.3.0 and V11.3.1 on the Arm Cortex-R82 (Armv8-R AArch64) MPU port might allow, under certain conditions, an unprivileged task on MPU-enabled builds to read or write privileged kernel memory beyond the validated buffer window, via a stream buffer system call. To remediate this issue, users should upgrade to version V11.3.2 or later.

Affected products (as reported)

Vendor	Product	Versions
FreeRTOS	FreeRTOS-Kernel	11.3.0 – through 11.3.1

Weakness: CWE-197, CWE-787, CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V11.3.2 release-notes, patch
https://aws.amazon.com/security/security-bulletins/2026-138-aws/ vendor-advisory
https://github.com/FreeRTOS/FreeRTOS-Kernel/security/advisories/GHSA-qf4j-6f5j-876g third-party-advisory