CVE-2026-109588
CRITICAL 9.3Numeric 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.
Severe if exploited (CVSS 9.3), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 5th percentile
Impact if exploited
9.3CVSS 4.0 · CRITICAL
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ⚠Access: Requires local access to the host
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Data snapshot:
Weakness (CWE)
- CWE-197: Numeric truncation error
- CWE-787: Out-of-bounds write
- CWE-125: Out-of-bounds read
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
References and research data (JSON)
All CVSS metrics
- HIGH 8.8 v3.1 · CNA Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - CRITICAL 9.3 v4.0 · CNA Primary
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - CRITICAL 9.3 v4.0 · NVD Secondary
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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 - HIGH 8.8 v3.1 · NVD Secondary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
References
Patches & mitigations
- https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V11.3.2 CVE record · AMZN · Updated 2026-10-16T17:18:18.351Z
NVD · CVE-2026-109588 · Updated 2026-10-20T19:17:28.967
Advisories
- https://aws.amazon.com/security/security-bulletins/2026-138-aws/ CVE record · AMZN · Updated 2026-10-16T17:18:18.351Z
NVD · CVE-2026-109588 · Updated 2026-10-20T19:17:28.967 - https://github.com/FreeRTOS/FreeRTOS-Kernel/security/advisories/GHSA-qf4j-6f5j-876g CVE record · AMZN · Updated 2026-10-16T17:18:18.351Z
NVD · CVE-2026-109588 · Updated 2026-10-20T19:17:28.967 - https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-102951 EUVD · EUVD-2026-102951