{"id":"CVE-2026-79978","published":"2026-10-23T20:17:27.657","lastModified":"2026-10-26T13:52:21.763","description":"The RTIO streaming completion callback adxl345_process_fifo_samples_cb() in drivers/sensor/adi/adxl345/adxl345_stream.c clamps the amount of FIFO data it will report (read_len = MIN(fifo_bytes, buf_avail)) to the space actually returned by rtio_sqe_rx_buf(), but then queues one 6-byte bus read per hardware FIFO entry at consecutive offsets from read_buf, bounded by the device-reported entry count rather than by the clamp. When the allocated buffer is smaller than a full batch, the driver writes up to 186 bytes past the end of the allocation; a companion defect left data->fifo_total_bytes un-reset at batch start, so an aborted or errored chain could leave a stale write offset that pushes the next batch's writes out of bounds as well.\n\nA short buffer is an expected, first-class outcome of the RTIO allocator: rtio_block_pool_alloc() walks the requested size down one block at a time until a contiguous run is available, and the driver only demands sizeof(struct adxl345_fifo_data) + 6 bytes as its minimum. Any streaming configuration whose mempool block granularity is smaller than a full FIFO batch (204 bytes) — for example the sensor shell's RTIO_DEFINE_WITH_MEMPOOL(sensor_read_rtio, 8, 8, 32, 64, 4) used by sensor stream <dev> on fifo_wm incl, or the 16-byte-block streaming example in the documentation — takes this path whenever the pool is fragmented or the consuming thread falls behind.\n\nThe out-of-bounds writes are performed by the I2C/SPI RTIO backend (DMA on many SoCs) into the shared RTIO block pool, corrupting neighbouring live buffers or, for a pool smaller than one batch, memory beyond the pool itself. The written bytes are accelerometer samples and the destination follows the allocation, so there is no controllable corruption primitive: the realistic impact is silent corruption of other RTIO consumers' data or a crash. Reaching it requires a board with an interrupt-wired ADXL345 built with CONFIG_ADXL345_STREAM, plus buffer-pool starvation, which a co-resident local workload can induce but which also occurs spontaneously under load; there is no network, USB or radio path to this code.","cvssScore":3.6,"cvssSeverity":"LOW","cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L","cwes":["CWE-787"],"vendors":[],"products":[],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/3451bb1e1e9165844060551164adb8a756e7b6b7","tags":[]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4v56-r4qm-v964","tags":[]}],"exploitRefs":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/3451bb1e1e9165844060551164adb8a756e7b6b7","tags":[]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4v56-r4qm-v964","tags":[]}],"hasPoc":true,"ai":null}