CVE-2026-109588 Numeric truncation in the MPU buffer authorization check in FreeRTOS-Kernel
An integer truncation flaw in FreeRTOS allows unprivileged tasks to access privileged kernel memory via stream buffer calls on specific Arm Cortex-R82 MPU builds.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109588?
CVE-2026-109588 is a critical vulnerability in FreeRTOS-Kernel, published on 16 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Which versions are affected by CVE-2026-109588?
How do I fix CVE-2026-109588?
No fix has been published for CVE-2026-109588 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-109588 being exploited?
There is no known exploitation of CVE-2026-109588 in the wild and no public exploit code.
Sources
Also known as GHSA-qf4j-6f5j-876g.