# CVE-2021-42553: micropython: A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronicsin versions before 3.5.1 allows an attacker...

CVE-2021-42553 is fixed in micropython on 1 platform, first by micropython 1.12-1ubuntu0.1~esm1, released September 17, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-42553
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0130
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 21, 2022

## Description

A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronicsin versions before 3.5.1 allows an attacker to execute arbitrary code whenthe descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. Thelibrary is typically integrated when using a RTOS such as FreeRTOS on STM32MCUs.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | micropython Ubuntu 20.04 LTS (focal) | 1.12-1ubuntu0.1~esm1 | [micropython 1.12-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-micropython-1.12-1ubuntu0.1-esm1.md) | Sep 17, 2024 |
| Linux | micropython Ubuntu 22.04.1 LTS (jammy) | 1.17+ds-1.1ubuntu2+esm1 | [micropython 1.17+ds-1.1ubuntu2+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-micropython-1.17-ds-1.1ubuntu2-esm1.md) | Sep 17, 2024 |
| Linux | micropython Ubuntu 24.04.5 LTS (noble) | 1.22.1+ds-1ubuntu0.24.04.1~esm1 | [micropython 1.22.1+ds-1ubuntu0.24.04.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-micropython-1.22.1-ds-1ubuntu0.24.04.1-esm1.md) | Sep 17, 2024 |
| Linux | micropython Ubuntu 24.10 (oracular) | 1.22.1+ds-1ubuntu0.24.10.1 | [micropython 1.22.1+ds-1ubuntu0.24.10.1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-micropython-1.22.1-ds-1ubuntu0.24.10.1.md) | Jan 16, 2026 |

---

Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.