Usb bluetooth device ACL read cb buffer overflow

published 2023-01-11 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27171

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits: 0; none known

usb device bluetooth class includes a buffer overflow related to implementation of net_buf_add_mem.

Patch / fix

fixed in 1

zephyrproject zephyr 3.0.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 19 mo ago (2025-04-09)

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

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	8.8	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

zephyrproject-rtos zephyr

Classification

Weakness

CWE-122 Heap-based Buffer Overflow
CWE-120 Buffer Copy without Checking Size of Input

References

github.com /zephyrproject-rtos/zephyr/security/advisories/GHSA-hfxq-3w6x-fv2m
third-party-advisory

Sources

CVE List CVE-2021-3966
NVD CVE-2021-3966

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