{"id":"CVE-2026-79978","state":"PUBLISHED","title":"Out-of-bounds write in the ADXL345 sensor driver RTIO streaming FIFO read path","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.","publishedAt":"2026-10-23T19:56:14.995Z","updatedAt":"2026-10-23T19:56:14.995Z","severity":{"score":3.6,"label":"Low","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L","source":"zephyr"},"assigner":"zephyr","products":["zephyrproject zephyr"],"affected":[{"vendor":"zephyrproject","product":"zephyr","packageName":"zephyr","defaultStatus":"unaffected","versions":[{"version":"4.0.0","status":"affected","lessThanOrEqual":"4.4.2","versionType":"semver"}],"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","programFiles":["drivers/sensor/adi/adxl345/adxl345_stream.c"],"programRoutines":[{"name":"adxl345_process_fifo_samples_cb"}]}],"references":["https://github.com/zephyrproject-rtos/zephyr/commit/3451bb1e1e9165844060551164adb8a756e7b6b7","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4v56-r4qm-v964"],"weaknesses":["CWE-787"],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/79xxx/CVE-2026-79978.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-79978","state":"PUBLISHED","datePublished":"2026-10-23T19:56:14.995Z","dateUpdated":"2026-10-23T19:56:14.995Z","assignerShortName":"zephyr","assignerOrgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","dateReserved":"2026-08-25T16:06:30.868Z"},"containers":{"cna":{"title":"Out-of-bounds write in the ADXL345 sensor driver RTIO streaming FIFO read path","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"zephyrproject","product":"zephyr","packageName":"zephyr","defaultStatus":"unaffected","versions":[{"version":"4.0.0","status":"affected","lessThanOrEqual":"4.4.2","versionType":"semver"}],"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","programFiles":["drivers/sensor/adi/adxl345/adxl345_stream.c"],"programRoutines":[{"name":"adxl345_process_fifo_samples_cb"}]}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/3451bb1e1e9165844060551164adb8a756e7b6b7","name":"Fix commit","tags":["patch"]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4v56-r4qm-v964","name":"GHSA-4v56-r4qm-v964"}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L","baseScore":3.6,"baseSeverity":"LOW"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"bounds","type":"CWE"}]}],"providerMetadata":{"shortName":"zephyr","orgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","dateUpdated":"2026-10-23T19:56:14.995Z"},"x_generator":{"engine":"cvelib 1.8.0"}}}}}