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CVE-2026-10680— Out-of-bounds access in Zephyr BR/EDR L2CAP configuration request handling via `uint16_t` length underflow

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组织开源的一款实时操作系统内核。 zephyrproject zephyr 4.2.0至4.3.1之前版本和4.4.0至4.4.1及之前版本存在缓冲区错误漏洞，该漏洞源于Classic (BR/EDR) L2CAP信号处理程序l2cap_br_conf_req()和l2cap_br_conf_rsp()中，使用buf->len代替len验证最小命令大小，导致opt_len下溢，未经身份验证的攻击者可在无线电范围内建立ACL连接后触发越界读

CVSS 7.6 · High EPSS 0.16% · P5

Affected Version Matrix 2

VendorProduct Version RangeStatus
zephyrproject zephyr 4.2.0< 4.3.1 affected
4.4.0≤ 4.4.1 affected
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I. Basic Information for CVE-2026-10680

Vulnerability Information
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Vulnerability Title
Out-of-bounds access in Zephyr BR/EDR L2CAP configuration request handling via `uint16_t` length underflow
Source: CVE Program / CVE List V5
Vulnerability Description
The Classic (BR/EDR) L2CAP signaling handlers l2cap_br_conf_req() and l2cap_br_conf_rsp() in subsys/bluetooth/host/classic/l2cap_br.c validated the minimum command size against buf->len (the bytes remaining in the whole received PDU) instead of len (the per-command data length from the L2CAP signaling header). Because multiple signaling commands can be packed into one PDU, buf->len may exceed a command's len. An attacker can send a CONF_REQ command with a header length smaller than the configuration-request structure (e.g. 0), followed by another command so that buf->len still satisfies the check. The check then passes incorrectly and opt_len = len - sizeof(*req) underflows the uint16_t to a near-0xFFFF value. The configuration-option loop, which lacks an opt_len-versus-buf->len guard, then walks far past the end of the pooled ACL receive buffer using net_buf pull primitives that perform no runtime bounds check, producing an out-of-bounds read of host memory and, when the out-of-bounds option bytes encode an MTU or flush-timeout option, an out-of-bounds write. The BR/EDR signaling channel is processed before pairing/encryption and an L2CAP channel to an L0 service such as SDP can be opened without pairing, so an unauthenticated peer within radio range that can establish an ACL connection can trigger the flaw, leading to memory corruption and denial of service (host/device crash). The defect is present in released versions including v4.4.0. The fix validates against len instead of buf->len in both handlers.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5
Vulnerability Title
zephyrproject zephyr 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
zephyrproject zephyr是zephyrproject组织开源的一款实时操作系统内核。 zephyrproject zephyr 4.2.0至4.3.1之前版本和4.4.0至4.4.1及之前版本存在缓冲区错误漏洞，该漏洞源于Classic (BR/EDR) L2CAP信号处理程序l2cap_br_conf_req()和l2cap_br_conf_rsp()中，使用buf->len代替len验证最小命令大小，导致opt_len下溢，未经身份验证的攻击者可在无线电范围内建立ACL连接后触发越界读
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 4.2.0 ~ 4.3.1 -

II. Public POCs for CVE-2026-10680

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III. Intelligence Information for CVE-2026-10680

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Patches & Fixes for CVE-2026-10680 (1)

Vendor Advisories for CVE-2026-10680 (1)

Same Patch Batch · zephyrproject · 2026-07-21 · 6 CVEs total

CVE-2026-10678 8.1 HIGH NULL-pointer / out-of-bounds write in Zephyr MCTP I2C+GPIO target binding driven by an una
CVE-2026-10677 6.5 MEDIUM Kernel heap memory leak in `z_vrfy_k_poll()` lets an unprivileged user thread exhaust the
CVE-2026-10674 5.5 MEDIUM DoS (hard fault) in NXP LPUART driver: unsupported runtime UART config leaves clocks disab
CVE-2026-10675 4.3 MEDIUM Bluetooth Mesh PB-ADV: invalidated provisioning link kept alive indefinitely, blocking (re
CVE-2026-10679 3.3 LOW Divide-by-zero in DesignWare SPI driver reachable from spi_transceive syscall (local DoS)

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-125

V. Comments for CVE-2026-10680

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