Is CVE-2021-42553 in the CISA KEV catalog?

No. CVE-2021-42553 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-42553?

CVE-2021-42553 has a CVSS v3 base score of 6.8 (MEDIUM).

What is the EPSS score for CVE-2021-42553?

CVE-2021-42553 has an EPSS score of 0.96% (57th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-42553?

Upgrade micropython on ubuntu 20.04 to 1.12-1ubuntu0.1~esm1 or later.

CVE & CISA-KEV Catalog

CVE-2021-42553

MEDIUM

6.8

CVSS v3

NVD

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.

CWE-120Classic Buffer Overflow

How to fix

Remediation Available

micropythonUbuntu

Fixed in:1.12-1ubuntu0.1~esm1USN-7472-1

Fixed in:1.17+ds-1.1ubuntu2+esm1USN-7472-1

Fixed in:1.22.1+ds-1ubuntu0.24.04.1~esm1USN-7472-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorPhysical

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.96%probability of exploitation in 30 days

57thpercentile

Moderate risk: more likely to be exploited than 57% of all known CVEs.

References

Patch1

github.com

Other references1

github.com

Related Vulnerabilities

Other CWE-120 (Classic Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0195	Medium	6.8	100%	-	Fix
CVE-2017-7269	Critical	9.8	100%	KEV	-
CVE-2019-11043	High	8.7	99%	KEV + Ransom	Fix
CVE-2011-4862	High	10.0	95%	-	Fix
CVE-2007-5659	High	7.8	94%	KEV	Fix
CVE-2022-3786	High	7.5	91%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-05-07.