{"id":"UBUNTU-CVE-2026-79978","details":"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-\u003efifo_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. A 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 \u003cdev\u003e 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. The 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.","modified":"2026-10-27T04:17:56.922600970Z","published":"2026-10-26T00:00:00Z","upstream":["CVE-2026-79978"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-79978"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-79978"},{"type":"REPORT","url":"https://github.com/zephyrproject-rtos/zephyr/commit/3451bb1e1e9165844060551164adb8a756e7b6b7"},{"type":"REPORT","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4v56-r4qm-v964"}],"affected":[{"package":{"name":"zephyr","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1","3.1.2-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.2-1build1","binary_name":"libzephyr4"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1build1"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build1"},{"binary_version":"3.1.2-1build1","binary_name":"zephyr-server"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79978.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1build1","3.1.2-1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1build2"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1build2"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build2"},{"binary_version":"3.1.2-1build2","binary_name":"zephyr-server"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79978.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1build3"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.2-1build3","binary_name":"libzephyr4"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1build3"},{"binary_version":"3.1.2-1build3","binary_name":"zephyr-clients"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79978.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1build3"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1build3"},{"binary_version":"3.1.2-1build3","binary_name":"libzephyr4-krb5"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79978.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1.1","3.1.2-1.1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1.1build1"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1.1build1"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1.1build1"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1.1build1"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1.1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79978.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-4"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.2-4","binary_name":"libzephyr4"},{"binary_version":"3.1.2-4","binary_name":"libzephyr4-krb5"},{"binary_version":"3.1.2-4","binary_name":"zephyr-clients"},{"binary_name":"zephyr-server","binary_version":"3.1.2-4"},{"binary_version":"3.1.2-4","binary_name":"zephyr-server-krb5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79978.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1.1build1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