CVE-2026-42808: Bosch Sensortec COINES_SDK Buffer Overflow

CVE-2026-42808 Overview

CVE-2026-42808 is a buffer overflow vulnerability [CWE-120] in Bosch Sensortec COINES_SDK versions 2.0 through 2.11. The flaw resides in the host streaming API function coines_read_stream_sensor_data(), which fails to validate the boundaries of the caller-provided destination buffer. A malicious or compromised hardware board connected via USB or Bluetooth Low Energy (BLE) can stream a high volume of sensor samples to trigger a heap or stack-based buffer overflow on the host desktop environment. Successful exploitation can result in Denial of Service (DoS) or potential arbitrary code execution on the host machine.

Critical Impact

A compromised sensor board can overflow host memory buffers over USB or BLE, enabling arbitrary code execution on developer workstations running the COINES_SDK.

Affected Products

• Bosch Sensortec COINES_SDK version 2.0 through 2.11
• Host desktop environments consuming the coines_read_stream_sensor_data() API
• Applications using COINES_SDK streaming interfaces over USB or BLE

Discovery Timeline

• 2026-09-10 - CVE-2026-42808 published to the National Vulnerability Database (NVD)
• 2026-09-10 - Last updated in NVD database

Technical Details for CVE-2026-42808

Vulnerability Analysis

The vulnerability originates in the host-side streaming pipeline of the COINES_SDK. The API function coines_read_stream_sensor_data() accepts a caller-provided destination buffer along with a number_of_samples argument that should bound the amount of data written. Under normal operation, this argument would constrain the copy to the memory allocation the caller reserved.

Internally, however, comm_intf_process_stream_response() discards the requested number_of_samples argument. Instead, it copies the entirety of the streaming ring buffer's accumulated data into the intermediate buffer coines_stream_rsp_buf. The higher-level API then executes an unconditional memcpy of the full ring buffer size into the caller's destination buffer.

Because no boundary check compares the ring buffer's data length against the caller's allocation size, any stream response larger than the caller anticipated overwrites adjacent heap or stack memory. This corrupts host process state and can be shaped into a code execution primitive.

Root Cause

The root cause is missing bounds validation across two abstraction layers. The stream processor ignores the caller's size expectation, and the reader function trusts the internal buffer size without cross-checking the destination allocation. This is a classic buffer copy without checking the size of input [CWE-120].

Attack Vector

Exploitation requires physical or proximate access. An attacker supplies a malicious Bosch development board, or compromises the firmware of an existing board, then connects it to a host machine over USB or BLE. Once the host application invokes stream reads, the board returns a crafted high-volume sample stream that overflows the destination buffer on the host. The vulnerability requires no authentication or user interaction beyond initiating the sensor stream.

No verified public proof-of-concept code is available. Refer to the Bosch Security Advisory BOSCH-SA-223618 for vendor technical details.

Detection Methods for CVE-2026-42808

Indicators of Compromise

• Unexpected crashes or memory corruption faults in host processes linking against COINES_SDK 2.0 through 2.11
• Anomalous USB or BLE sensor device enumeration followed by abnormally large stream response payloads
• Host process termination or signals such as SIGSEGV or SIGABRT during calls to coines_read_stream_sensor_data()

Detection Strategies

• Inventory developer workstations and CI/test hosts for installations of COINES_SDK versions in the affected range
• Monitor USB device connection events and correlate with subsequent crashes in tools that embed the SDK
• Enable heap protection and stack canary telemetry on host builds to surface overflow attempts at runtime

Monitoring Recommendations

• Log all connections of Bosch Sensortec evaluation boards and other supported hardware to engineering workstations
• Alert on unsigned or unexpected firmware images loaded onto sensor boards connected to corporate hosts
• Track process crash telemetry for binaries statically or dynamically linked against libcoines or equivalent SDK components

How to Mitigate CVE-2026-42808

Immediate Actions Required

• Restrict the connection of untrusted or unverified sensor development boards to hosts running COINES_SDK
• Update to a fixed COINES_SDK release as published by Bosch Sensortec in advisory BOSCH-SA-223618
• Audit internal applications that call coines_read_stream_sensor_data() and add caller-side size validation where feasible

Patch Information

Refer to the Bosch Security Advisory BOSCH-SA-223618 for the vendor-provided fixed version and upgrade guidance. Users of COINES_SDK versions 2.0 through 2.11 should upgrade to the patched release identified in the advisory.

Workarounds

• Physically disconnect Bosch sensor boards when not actively in use for development or testing
• Disable BLE pairing for COINES-compatible boards on hosts that do not require wireless streaming
• Wrap SDK stream calls in an application-level shim that validates the internal ring buffer size before returning data to callers

# Verify installed COINES_SDK version on Linux hosts
dpkg -l | grep -i coines
find / -name "libcoines*" -exec strings {} \; | grep -i "version"