CVE-2020-10021

Out-of-bounds write in USB Mass Storage with unaligned sizes

8.1 High

Out-of-bounds Write in the USB Mass Storage memoryWrite handler with unaligned Sizes See NCC-ZEP-024, NCC-ZEP-025, NCC-ZEP-026 This issue affects: zephyrproject-rtos zephyr version 1.14.1 and later versions. version 2.1.0 and later versions.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.41%Down 0.8 points since Apr 14, 2021

What each source reports

CVE List Score used 8.1

Out-of-bounds write in USB Mass Storage with unaligned sizes

Record: CVE-2020-10021
CVSS 3.1: 8.1 HighCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

EUVDEUVD-2020-2486 8.1

Record: EUVD-2020-2486
CVSS 3.1: 8.1 HighCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-7r7c-7m5r-6gpx 7.8

Out-of-bounds Write in the USB Mass Storage memoryWrite handler with unaligned Sizes See NCC-ZEP...

Record: GHSA-7r7c-7m5r-6gpx
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

NVD 8.1

Record: CVE-2020-10021
CVSS 3.1: 8.1 HighCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 4.6 MediumAV:L/AC:L/Au:N/C:P/I:P/A:P
Weakness: CWE-787
Updated: 2026-11-02

Affected products

History

History
Recorded	Changed	Sources
Nov 10, 2026	facts
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-10021 is a high vulnerability (CVSS 8.1) in Zephyrproject Zephyr, published May 11, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. No source names a fixed version.