Buffer overflow in Zephyr USB DFU DNLOAD

published 2021-10-05 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26928

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.3%; EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits: 0; none known

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

Patch / fix

fixed in 1

zephyrproject zephyr 2.7.0

Exploit prediction

2.31% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c3gr-hgvr-f363 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.6	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

zephyrproject-rtos zephyr

Classification

Weakness

CWE-122 Heap-based Buffer Overflow
CWE-787 Out-of-bounds Write

References

github.com /zephyrproject-rtos/zephyr/security/advisories/GHSA-c3gr-hgvr-f363
exploit, third-party-advisory

Sources

CVE List CVE-2021-3625
NVD CVE-2021-3625

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary