CVE-2026-42806

An out-of-bounds read vulnerability was discovered in the Bosch BME690 SensorAPI (C-driver) in version v1.0.3 and prior, specifically within the field data parsing logic in read_all_field_data (bme69x.c).

The driver prefetches heater configuration registers into a contiguous 30-byte stack buffer (set_val) mapping IDAC, RES_HEAT, and GAS_WAIT tables.

When parsing sensor field data, the gas_index is extracted using a 4-bit mask (0..15) but lacks boundary verification against the valid range (0..9).

An attacker or a compromised peripheral mimicking a sensor on the I2C/SPI bus could return a payload with a gas index value of 10 or higher.

This causes the driver to perform an out-of-bounds array access (set_val[20 + gas_index]), reading up to 6 bytes past the stack buffer.

The leaked out-of-bounds byte is then written into the public gas_wait field, which may lead to measurement corruption or leak adjacent stack memory when telemetered or logged.