What’s Vulnerable › Vulnerabilities

CVE-2021-43997

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-11-17 · updated 2026-06-17

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.

Affected products

• FreeRTOS-Kernel: from 10.2.0 before 10.4.6; 10.4.3-patch1 — fixed in 10.4.6

How to fix

Upgrade to a fixed version: FreeRTOS-Kernel 10.4.6. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.4.3-LTS-Patch-2
• 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
• 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
• 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
• https://github.com/FreeRTOS/FreeRTOS-Kernel/releases/tag/V10.5.0

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