CVE-2021-42553

Name: CVE-2021-42553
Creator: NVD / NIST
Published: 2022-10-21T10:15:12.47+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.96%

Last modified Jun 17, 2026

CVE-2021-42553 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronics in versions before 3.5.1 allows an attacker to execute arbitrary code when the descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. The library is typically integrated when using a RTOS such as FreeRTOS on STM32 MCUs.. EPSS estimates a 0.96% chance of exploitation in the next 30 days.

Description

A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronics in versions before 3.5.1 allows an attacker to execute arbitrary code when the descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. The library is typically integrated when using a RTOS such as FreeRTOS on STM32 MCUs.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.96%

57.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
St	Stm32 Mw Usb Host	All versions

References

https://github.com/STMicroelectronics/stm32_mw_usb_host
https://github.com/STMicroelectronics/stm32_mw_usb_host/pull/4Patch, Third Party Advisory
https://github.com/STMicroelectronics/stm32_mw_usb_host
https://github.com/STMicroelectronics/stm32_mw_usb_host/pull/4Patch, Third Party Advisory

Timeline

Published: Oct 21, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42553?

How severe is CVE-2021-42553?

CVE-2021-42553 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.96% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42553?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-42553?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST