← Vulnerability feed

Vulnerability record · CVE-2021-43997 · published 17 November 2021

CVE-2021-43997: Amazon freertos vulnerability

Amazon · Freertos

FreeRTOS versions 10.2.0 through 10.4.5 do not prevent non-kernel code from calling the xPortRaisePrivilege internal function to raise privilege. FreeRTOS versions through 10.4.6 do not prevent a third party that has already independently gained the ability to execute injected code to achieve further privilege escalation by branching directly inside a FreeRTOS MPU API wrapper function with a manually crafted stack frame. These issues affect ARMv7-M MPU ports, and ARMv8-M ports with MPU support enabled (i.e. configENABLE_MPU set to 1). These are fixed in V10.5.0 and in V10.4.3-LTS Patch 3.

7.8 CVSS 3.1 High EPSS 0.34% · top 75.2%
7.8CVSS 3.1 base score, v2 7.2
0.34%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

FreeRTOS versions 10.2.0 through 10.4.5 do not prevent non-kernel code from calling the xPortRaisePrivilege internal function to raise privilege. FreeRTOS versions through 10.4.6 do not prevent a third party that has already independently gained the ability to execute injected code to achieve further privilege escalation by branching directly inside a FreeRTOS MPU API wrapper function with a manually crafted stack frame. These issues affect ARMv7-M MPU ports, and ARMv8-M ports with MPU support enabled (i.e. configENABLE_MPU set to 1). These are fixed in V10.5.0 and in V10.4.3-LTS Patch 3.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.3-LTS-Patch-2 Release NotesThird Party Advisory
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.3-LTS-Patch-3
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.6 Release NotesThird Party Advisory
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.5.0
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.3-LTS-Patch-2 Release NotesThird Party Advisory
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.3-LTS-Patch-3
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.6 Release NotesThird Party Advisory
https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.5.0

Track CVE-2021-43997 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-32020Amazon freertos memory buffer overflow vulnerabilityThe kernel in Amazon Web Services FreeRTOS before 10.4.3 has insufficient bounds checking during management of heap memory.EPSS 1.3%9.8CVE-2021-31571Amazon freertos integer overflow vulnerabilityThe kernel in Amazon Web Services FreeRTOS before 10.4.3 has an integer overflow in queue.c for queue creation.EPSS 1.4%9.8CVE-2021-31572Amazon freertos integer overflow vulnerabilityThe kernel in Amazon Web Services FreeRTOS before 10.4.3 has an integer overflow in stream_buffer.c for a stream buffer.EPSS 1.4%9.3CVE-2026-77234Amazon freertos incorrect authorization vulnerabilityImproper input validation in FreeRTOS-Kernel before 11.3.1 might allow an unprivileged task on MPU-enabled ports to execute code in privileged kernel…EPSS 0.17%8.3CVE-2026-77235Amazon freertos use after free vulnerabilityMissing privilege verification in the secure context cleanup handler in FreeRTOS-Kernel before 11.3.1 might allow local users to cause a use-after-fr…EPSS 0.16%8.3CVE-2026-77236Amazon freertos out-of-bounds write vulnerabilityMissing minimum size validation in secure context allocation in FreeRTOS-Kernel before 11.3.1 might allow local users to corrupt secure-world heap me…EPSS 0.16%8.2CVE-2026-77237Amazon freertos out-of-bounds read vulnerabilityMissing queue-set type validation in xQueueAddToSet() in the FreeRTOS-Kernel before 11.3.1 might allow an unprivileged task on MPU-enabled ports with…EPSS 0.18%8.1CVE-2018-16601Amazon web services freertos vulnerabilityAn issue was discovered in Amazon Web Services (AWS) FreeRTOS through 1.3.1, FreeRTOS up to V10.0.1 (with FreeRTOS+TCP), and WITTENSTEIN WHIS Connect…EPSS 4.2%

Source: NIST National Vulnerability Database (record CVE-2021-43997), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.