---
id: CVE-2026-10593
title: >-
  Remotely triggerable NULL-pointer dereference in Bluetooth LE Audio BAP
  unicast client QoS-state handling
summary: >-
  The Zephyr Bluetooth LE Audio Basic Audio Profile (BAP) unicast client
  mishandles peer-supplied ASE state notifications. In
  unicast_client_ep_qos_state() (subsys/bluetooth/audio/bap_unicast_client.c),
  the handler writes attacker-controll…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-476
vendor: zephyrproject
product: zephyr
affected:
  - zephyr >= 4.3.0 < 4.3.1
  - zephyr >= 4.4.0 < 4.4.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-29T13:47:33.621798Z'
published: '2026-06-28'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:09:58.700Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-10593'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/commit/52f25c903f2926cb1281b50fd79654668e2d483f
    label: Fix commit
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-22q8-m94g-2pwh
    label: GHSA-22q8-m94g-2pwh
tags:
  - cve.org
epss: 0.00301
epssPercentile: 0.21236
ingestedAt: '2026-10-15T22:48:25.561Z'
---

## Overview

The Zephyr Bluetooth LE Audio Basic Audio Profile (BAP) unicast client mishandles peer-supplied ASE state notifications. In unicast_client_ep_qos_state() (subsys/bluetooth/audio/bap_unicast_client.c), the handler writes attacker-controlled QoS fields (interval, framing, phy, sdu, rtn, latency, pd) through the stream->qos pointer with only a stream != NULL guard. stream->qos is NULL for any stream that has been codec-configured via bt_bap_stream_config() but not yet added to a unicast group (it is set only by unicast_group_add_stream()).

A malicious or buggy remote ASCS server, to which the local device is connected as a BAP unicast client, can send a GATT notification announcing the ASE has entered the QoS Configured state while the local endpoint is still in the Codec Configured state — a transition the dispatcher explicitly permits — during that window, causing a write through a NULL pointer and a crash (denial of service). The data written is itself remote-controlled.

The defect shipped in v4.3.0 and v4.4.0 (and earlier). The fix re-points all BAP QoS storage to the always-valid embedded ep->qos struct, eliminating the NULL dereference.

## Affected

- `zephyr >= 4.3.0 < 4.3.1`
- `zephyr >= 4.4.0 < 4.4.2`

## Remediation

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