CVE-2020-10021Public exploit

Kernel memory corruption via unaligned USB writes

Published May 11, 2020 · Updated Sep 17, 2024

Out-of-bounds write in Zephyr RTOS USB Mass Storage 1.14.1 and 2.1.0 allows physically proximate attackers to corrupt kernel memory via USB. The memoryWrite loop indexes a fixed 512-byte page buffer using addr modulo 512 plus attacker-controlled packet offsets, allowing a transfer near the block boundary to overrun the buffer by up to 63 bytes. Exploitation requires a malicious USB host connected to a device with USB Mass Storage enabled; the resulting corruption produces a device crash or kernel code execution.

CVSS severity8.1
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Zephyr RTOS USB Mass Storage 1.14.1 and 2.1.0 allows physically proximate attackers to corrupt kernel memory via USB. The memoryWrite loop indexes a fixed 512-byte page buffer using addr modulo 512 plus attacker-controlled packet offsets, allowing a transfer near the block boundary to overrun the buffer by up to 63 bytes. Exploitation requires a malicious USB host connected to a device with USB Mass Storage enabled; the resulting corruption produces a device crash or kernel code execution.

The record

CVE
CVE-2020-10021
Published
May 11, 2020
Updated
Sep 17, 2024
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-787, T1200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.14.1 <unspecified
  2. Affected versionversion=2.1.0 <unspecified

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=1.14.1 <unspecified; version=2.1.0 <unspecified

Published CVSS scores

8.1Zephyr ProjectCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1200Hardware Additions

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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