CVE-2021-3625
Buffer overflow in Zephyr USB DFU DNLOAD
Buffer overflow in Zephyr USB DFU DNLOAD. Zephyr versions >= v2.5.0 contain Heap-based Buffer Overflow (CWE-122). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c3gr-hgvr-f363
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Buffer overflow in Zephyr USB DFU DNLOAD
Buffer overflow in Zephyr USB DFU DNLOAD. Zephyr versions >= v2.5.0 contain Heap-based Buffer Overflow (CWE-122). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c3gr-hgvr-f363
- Record
CVE-2021-3625- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
EUVDEUVD-2021-26928
Buffer overflow in Zephyr USB DFU DNLOAD. Zephyr versions >= v2.5.0 contain Heap-based Buffer Overflow (CWE-122). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c3gr-hgvr-f363
- Record
EUVD-2021-26928- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - Updated
- 2026-11-03
NVD
Buffer overflow in Zephyr USB DFU DNLOAD. Zephyr versions >= v2.5.0 contain Heap-based Buffer Overflow (CWE-122). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c3gr-hgvr-f363
- Record
CVE-2021-3625- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-122, CWE-787
- Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | szymonh/zephyr_cve-2021-3625 | 2021-10-06 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3625 is a critical vulnerability (CVSS 9.6) in Zephyrproject Zephyr, published October 5, 2021. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 2.31%, the 83rd percentile. No source names a fixed version.