---
id: CVE-2026-10658
title: >-
  A missing length validation in the Zephyr Bluetooth Host ISO receive path can
  be triggered by malformed HCI ISO data
summary: >-
  A missing length validation in the Zephyr Bluetooth Host ISO receive path can
  be triggered by malformed HCI ISO data. In bt_iso_recv()
  (subsys/bluetooth/host/iso.c), when processing PB=START/SINGLE fragments, the
  code pulls a TS SDU head…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'
cwe:
  - CWE-125
vendor: zephyrproject
product: zephyr
affected:
  - zephyr <= 4.4.1
published: '2026-06-23'
updated: '2026-07-06'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-10658'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-26g8-rmpf-j6cw
    label: vulnerabilities@zephyrproject.org
tags:
  - nvd
epss: 0.00282
epssPercentile: 0.18376
ingestedAt: '2026-07-06T19:45:46.945Z'
---

## Overview

A missing length validation in the Zephyr Bluetooth Host ISO receive path can be triggered by malformed HCI ISO data. In bt_iso_recv() (subsys/bluetooth/host/iso.c), when processing PB=START/SINGLE fragments, the code pulls a TS SDU header (8 bytes, ts=1) or a non-TS SDU header (4 bytes, ts=0) without first verifying that buf->len contains at least that many bytes. The outer HCI ISO length check in hci_iso() validates payload length consistency but not the minimum inner SDU header size, so a packet with payload length 1 passes hci_iso() and then reaches net_buf_pull_mem(), which asserts buf->len >= len. As a result, malformed ISO traffic deterministically triggers a kernel assert (denial of service) in assert-enabled builds, and in non-assert builds the same path may proceed with an undersized buffer, leading to out-of-bounds read behavior. The issue affects products using the Zephyr Host with CONFIG_BT_ISO_RX enabled, particularly where incoming HCI data can be influenced by a malicious or compromised controller or malformed forwarded ISO traffic.

## Affected

- `zephyr <= 4.4.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.