CVE-2026-109587: Incorrect authorization in the Arm Cortex-R82 MPU port in FreeRTOS-Kernel

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.1%

EPSS score, percentile 3.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

9.3 Critical

CVSS v4.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (2)

Which versions are affected?

Affected

• 11.3.0 through 11.3.1

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

• github.com (Release notes, Patch)
• aws.amazon.com (Vendor advisory)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unaffected.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

Incorrect authorization in the Arm Cortex-R82 (Armv8-R AArch64) MPU port in FreeRTOS-Kernel V11.3.0 and V11.3.1 might allow an unprivileged task on MPU-enabled builds to read and write privileged kernel memory outside the regions assigned to it, via a buffer argument passed to an MPU system call. To remediate this issue, users should upgrade to version V11.3.2 or later.

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-109587 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 16 Oct 2026.
• The CVE record carries a CVSS v4.0 base score of 9.3 (Critical), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.1% (percentile 3.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact total.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

Incorrect authorization in the Arm Cortex-R82 MPU port in FreeRTOS-Kernel

Incorrect authorization in the Arm Cortex-R82 (Armv8-R AArch64) MPU port in FreeRTOS-Kernel V11.3.0 and V11.3.1 might allow an unprivileged task on MPU-enabled builds to read and write privileged kernel memory outside the regions assigned to it, via a buffer argument passed to an MPU system call. To remediate this issue, users should upgrade to version V11.3.2 or later.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline