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CVE-2026-11893— Double free / use-after-free in Bouffalo Lab HCI driver send() error paths (hci_bflb)

Quick assessment

Affected
zephyrproject zephyr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

zephyrproject zephyr是zephyrproject组织开源的一个面向物联网设备的实时操作系统。 zephyrproject zephyr 4.4.0版本至4.4.2之前版本存在资源管理错误漏洞，该漏洞源于蓝牙HCI驱动中缓冲区所有权处理错误，错误路径上调用net_buf_unref导致双重释放和释放后重用，可能造成拒绝服务或内存损坏。

CVSS 5.9 · Medium EPSS 0.25% · P14

Affected Version Matrix 1

VendorProduct Version RangeStatus
zephyrproject zephyr 4.4.0< 4.4.2 affected
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I. Basic Information for CVE-2026-11893

Vulnerability Information
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Vulnerability Title
Double free / use-after-free in Bouffalo Lab HCI driver send() error paths (hci_bflb)
Source: CVE Program / CVE List V5
Vulnerability Description
The Bluetooth HCI driver for Bouffalo Lab on-chip BLE controllers (BL60x/BL70x/BL61x), bt_bflb_send() in drivers/bluetooth/hci/hci_bflb.c, violates the bt_hci_driver_api.send() buffer-ownership contract. That contract (documented at include/zephyr/drivers/bluetooth.h) requires the buffer reference to be consumed only on success; on error the caller still owns the reference and unrefs it. The driver instead routed all error paths through a shared label that unconditionally called net_buf_unref(buf) before returning the error code, consuming the buffer on failure as well. When send() returns an error, the host TX path (send_buf() in subsys/bluetooth/host/conn.c) unrefs the same buffer again, believing it still owns it. This double-unref over-decrements the net_buf reference count. Because the buffer is a TX fragment whose destroy callback also decrements its still-queued parent buffer, the parent is freed prematurely while reachable on the connection TX queue, producing a use-after-free and corruption of the shared net_buf pool rather than a benign leak. The error conditions are on the host-to-controller transmit path (controller send failure, or an unsupported H:4 packet type), so they are not driven directly by attacker-supplied radio bytes; a remote/adjacent peer can influence them only indirectly, e.g. by inducing controller TX failures under heavy link load. The consequence when reached is BLE-stack denial of service (crash / pool corruption) with possible further memory corruption, bounded to devices using one of these Bouffalo Lab on-chip controllers.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
双重释放
Source: CVE Program / CVE List V5
Vulnerability Title
zephyrproject zephyr 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
zephyrproject zephyr是zephyrproject组织开源的一个面向物联网设备的实时操作系统。 zephyrproject zephyr 4.4.0版本至4.4.2之前版本存在资源管理错误漏洞，该漏洞源于蓝牙HCI驱动中缓冲区所有权处理错误，错误路径上调用net_buf_unref导致双重释放和释放后重用，可能造成拒绝服务或内存损坏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject zephyr 4.4.0 ~ 4.4.2 -

II. Public POCs for CVE-2026-11893

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III. Intelligence Information for CVE-2026-11893

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Patches & Fixes for CVE-2026-11893 (1)

Vendor Advisories for CVE-2026-11893 (1)

Same Patch Batch · zephyrproject · 2026-08-11 · 5 CVEs total

CVE-2026-11894 5.9 MEDIUM Double-free / use-after-free in Realtek BEE Bluetooth HCI driver `send()` error paths
CVE-2026-12052 5.2 MEDIUM Out-of-bounds write in USB CDC NCM control handler when host wLength is smaller than the r
CVE-2026-12051 4.6 MEDIUM NULL pointer dereference in USB DFU device_next download handler (handle_download)
CVE-2026-11985 3.6 LOW Cross-thread FPU register leak on ARM when FPU enabled without register sharing

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-415

V. Comments for CVE-2026-11893

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