DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer

published 2023-02-26 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26660

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 19 mo ago (2025-03-11)

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

zephyrprojectsec.atlassian.net https://zephyrprojectsec.atlassian.net/browse/ZEPSEC-117 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	6.5	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

zephyrproject-rtos zephyr

Classification

Weakness

CWE-703 Improper Check or Handling of Exceptional Conditions
CWE-665 Improper Initialization

References

zephyrprojectsec.atlassian.net /browse/ZEPSEC-117
exploit, issue-tracking, vendor-advisory

Sources

CVE List CVE-2021-3329
NVD CVE-2021-3329

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