How severe is CVE-2020-10021?

CVE-2020-10021 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-10021 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-10021?

CVE-2020-10021 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-10021?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-10021 published?

CVE-2020-10021 was published on 2020-05-11 and last updated on 2026-06-17.

CVE-2020-10021

CVE-2020-10021 is a high-severity vulnerability in Zephyrproject Zephyr with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 4.6
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Zephyrproject Zephyr
Published: 2020-05-11
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-10021?: 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.
How severe is CVE-2020-10021?: CVE-2020-10021 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-10021 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-10021?: CVE-2020-10021 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-10021?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-10021 published?: CVE-2020-10021 was published on 2020-05-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*

More vulnerabilities in Zephyrproject Zephyr

CVE-2026-5067 — Critical (CVSS 9.8): A remote, unauthenticated attacker can trigger memory corruption in Zephyr's HTTP server WebSocket upgrade path by…
CVE-2022-3806 — Critical (CVSS 9.8): Inconsistent handling of error cases in bluetooth hci may lead to a double free condition of a network buffer.
CVE-2017-14199 — Critical (CVSS 9.8): A buffer overflow has been found in the Zephyr Project's getaddrinfo() implementation in 1.9.0 and 1.10.0.
CVE-2018-1000800 — Critical (CVSS 9.8): zephyr-rtos version 1.12.0 contains a NULL base pointer reference vulnerability in sys_ring_buf_put(),…
CVE-2021-3329 — Critical (CVSS 9.6): Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
CVE-2023-0397 — Critical (CVSS 9.6): A malicious / defect bluetooth controller can cause a Denial of Service due to unchecked input in…

All CVEs affecting Zephyrproject Zephyr →

Other CWE-787 (Out-of-bounds Write) vulnerabilities

CVE-2026-42369 — Critical (CVSS 10.0): GV-VMS V20 is a Video Monitoring Software used to gather the feeds of many surveillance cameras and manage other…
CVE-2026-4746 — Critical (CVSS 10.0): Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src‎ modules). This vulnerability is…
CVE-2025-43300 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 15.8.5 and iPadOS…
CVE-2025-24201 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in…
CVE-2024-42479 — Critical (CVSS 10.0): llama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause…
CVE-2024-39791 — Critical (CVSS 10.0): Stack-based buffer overflow vulnerabilities affecting Vonets industrial wifi bridge relays and wifi bridge…

Browse all CWE-787 (Out-of-bounds Write) vulnerabilities →