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CVE-2026-12236— Infinite loop (DoS) in Bluetooth GATT client parsing of Read-By-Type responses with zero data length

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.

漏洞描述如下： 在 文件中，Bluetooth 主机 GATT 客户端函数 在 BT_GATT_DISCOVER_STD_CHAR_DESC 发现过程中，解析来自远程 GATT 服务器的 ATT Read By Type Response（按类型读取响应）。该函数直接使用对端 PDU（协议数据单元）中的 作为每条记录的步长（per-entry stride），并在解析循环中既使用此值测试退出条件（ ），也用于更新指针（ ）。然而，在循环开始前，从未对 的最小值进行有效性验证。 恶意或对端设备发生故障时，可能回复 。

CVSS 6.5 · Medium EPSS 0.16% · P5

Affected Version Matrix 1

VendorProduct Version RangeStatus
zephyrproject zephyr 2.6.0< 4.4.2 affected
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I. Basic Information for CVE-2026-12236

Vulnerability Information
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Vulnerability Title
Infinite loop (DoS) in Bluetooth GATT client parsing of Read-By-Type responses with zero data length
Source: CVE Program / CVE List V5
Vulnerability Description
The Bluetooth host GATT client function parse_read_std_char_desc() in subsys/bluetooth/host/gatt.c parses an ATT Read By Type Response received from a remote GATT server during BT_GATT_DISCOVER_STD_CHAR_DESC discovery. The per-entry stride rsp->len is taken directly from the peer's PDU, and the parse loop both tests its exit condition (length >= rsp->len) and advances (length -= rsp->len, pdu += rsp->len) using that value. The minimum value of rsp->len was never validated before the loop. A malicious or malfunctioning peer can reply with rsp->len = 0. Because length is unsigned and never decreases, the loop condition stays true forever and the read pointer never advances; as long as the body is at least a few bytes with a non-zero handle and a matching descriptor UUID, the host repeatedly re-parses the same bytes and invokes the discovery callback, never terminating. This hangs the Bluetooth host processing thread (CWE-835, loop with unreachable exit condition). The condition is reachable by any connected peer once the local device initiates standard-descriptor-value discovery; GATT discovery does not require bonding or encryption, so an unauthenticated adjacent attacker that the device connects to can trigger it. The impact is denial of service of the Bluetooth subsystem (and likely a watchdog reset on constrained targets); there is no memory disclosure or corruption. The fix adds a rsp->len < sizeof(struct bt_att_data) check before the loop, rejecting under-length responses so the stride is always non-zero and the loop terminates. The sibling parsers parse_include() and parse_characteristic() already validated rsp->len and are unaffected.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不可达退出条件的循环(无限循环)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject zephyr 2.6.0 ~ 4.4.2 -

II. Public POCs for CVE-2026-12236

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III. Intelligence Information for CVE-2026-12236

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Patches & Fixes for CVE-2026-12236 (1)

Vendor Advisories for CVE-2026-12236 (1)

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-835

V. Comments for CVE-2026-12236

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