{"id":"CVE-2026-19737","summary":"NULL pointer dereference in the ESP32 I2S driver when triggering an unsupported direction","details":"i2s_esp32_trigger_check() in drivers/i2s/i2s_esp32.c validates the requested direction only for I2S_DIR_BOTH. The I2S_DIR_RX and I2S_DIR_TX branches read dev_cfg-\u003erx.data-\u003econfigured / dev_cfg-\u003etx.data-\u003econfigured without first checking the stream pointers. The device instantiation macro I2S_ESP32_STREAM_INIT() sets both .conf and .data to NULL for a direction the devicetree does not describe, so on an instance that wires only one direction — the normal shape for audio output or a worldsemi,ws2812-i2s LED strip — the other direction dereferences a NULL pointer instead of returning an error.\n\ni2s_trigger() is a Zephyr syscall, and z_vrfy_i2s_trigger() in drivers/i2s/i2s_handlers.c validates only the device object and the presence of the trigger API pointer; the dir argument is passed to the driver unvalidated. On a build with CONFIG_USERSPACE enabled, a user-mode thread that has been granted the I2S device can issue a single i2s_trigger() call naming the unwired direction and cause a load from address 0 in kernel mode. Among the Espressif parts that carry this driver, userspace is available in-tree only on RISC-V SoCs with CONFIG_RISCV_PMP, and v4.4.0 is the first release where that is buildable: the ESP32-C6 HPCORE selects RISCV_PMP when it is not built for MCUboot. ESP32-C5 in v4.4.x carries the same PMP-region and userspace linker support but does not select RISCV_PMP by default. Espressif Xtensa targets do not support Zephyr userspace, and in a non-userspace build the bad direction can only come from in-kernel application code.\n\nThe impact is limited to availability: the access is a read at offset 0 of the missing stream structure, so there is no attacker-controlled offset, no write primitive and no information disclosure. With the default fatal-error handler the resulting exception halts the system, giving an unprivileged user-mode thread a system-wide denial of service. The fix adds the same pointer check the I2S_DIR_BOTH branch already performed and returns -ENOSYS for a direction the instance does not implement; the driver's other entry points (i2s_esp32_config_check(), i2s_esp32_config_get(), i2s_esp32_read(), i2s_esp32_write()) already guarded the pointers, and a static audit found no equivalent unguarded path.\n\nThe driver defect is older than the affected range. The unguarded dereference is present from v4.2.0 (reached through i2s_esp32_trigger_stream(), whose if (stream) guard tests the address of a struct member and is never false) and takes its present i2s_esp32_trigger_check() form in v4.3.0. No in-tree Espressif configuration before v4.4.0 can run a user-mode thread, so in v4.2.x and v4.3.x the direction argument can only come from trusted kernel code. Those releases carry the bug but are not listed as affected; the fix has also been merged to v4.3-branch as hardening.","aliases":["GHSA-5g9q-h8wq-rrf3"],"modified":"2026-10-12T02:32:48.410918885Z","published":"2026-10-11T17:15:01.878Z","database_specific":{"cna_assigner":"zephyr","cwe_ids":["CWE-476"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19737.json","unresolved_ranges":[{"extracted_events":[{"introduced":"4.4.0"},{"fixed":"4.5.0"}],"source":"AFFECTED_FIELD"},{"source":"DESCRIPTION","extracted_events":[{"fixed":"i2s_esp32_trigger_stream"}]}]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19737.json"},{"type":"PACKAGE","url":"https://github.com/zephyrproject-rtos/zephyr"},{"type":"FIX","url":"https://github.com/zephyrproject-rtos/zephyr/commit/0d82dbbe72f154de32cc45021a9f59d9a737246b"},{"type":"ADVISORY","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-5g9q-h8wq-rrf3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19737"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zephyrproject-rtos/zephyr","events":[{"introduced":"0"},{"fixed":"684c9e8f32e4373a21098559f748f06915f950c9"}],"database_specific":{"source":"DESCRIPTION","extracted_events":[{"introduced":"0"},{"fixed":"v4.4.0"}]}}],"versions":["v4.4.0-rc3","v4.4.0-rc2","v4.4.0-rc1","v4.3.0","v4.3.0-rc3","v4.3.0-rc2","v4.3.0-rc1","v4.2.0","v4.2.0-rc3","v4.2.0-rc2","v4.2.0-rc1","v4.1.0","v4.1.0-rc3","v4.1.0-rc2","v4.1.0-rc1","v4.0.0","v4.0.0-rc3","v4.0.0-rc2","v4.0.0-rc1","v3.7.0","v3.7.0-rc3","v3.7.0-rc2","v3.7.0-rc1","v3.6.0","v3.6.0-rc3","v3.6.0-rc2","v3.6.0-rc1","zephyr-v3.5.0","v3.5.0","v3.5.0-rc3","v3.5.0-rc2","v3.5.0-rc1","zephyr-v3.4.0","v3.4.0","v3.4.0-rc3","v3.4.0-rc2","v3.4.0-rc1","zephyr-v3.3.0","v3.3.0","v3.3.0-rc3","v3.3.0-rc2","v3.3.0-rc1","zephyr-v3.2.0","v3.2.0","v3.2.0-rc3","v3.2.0-rc2","v3.2.0-rc1","zephyr-v3.1.0","v3.1.0","v3.1.0-rc3","v3.1.0-rc2","v3.1.0-rc1","zephyr-v3.0.0","v3.0.0","v3.0.0-rc3","v3.0.0-rc2","v3.0.0-rc1","v2.7.99","v2.7.0-rc3","v2.7.0-rc2","v2.7.0-rc1","zephyr-v2.6.0","v2.6.0","v2.6.0-rc3","v2.6.0-rc2","v2.6.0-rc1","zephyr-v2.5.0","v2.5.0","v2.5.0-rc4","v2.5.0-rc3","v2.5.0-rc2","v2.5.0-rc1","zephyr-v2.4.0","v2.4.0","v2.4.0-rc3","v2.4.0-rc2","v2.4.0-rc1","zephyr-v2.3.0","v2.3.0","v2.3.0-rc2","v2.3.0-rc1","zephyr-v2.1.0","v2.1.0","zephyr-v2.2.0","v2.2.0","v2.2.0-rc3","v2.2.0-rc2","v2.2.0-rc1","v2.1.0-rc3","v2.1.0-rc2","v2.1.0-rc1","zephyr-v2.0.0","v2.0.0","v2.0.0-rc3","v2.0.0-rc2","v2.0.0-rc1","zephyr-v1.14.0","v1.14.0","v1.14.0-rc3","v1.14.0-rc2","v1.14.0-rc1","zephyr-v1.13.0","v1.13.0","v1.13.0-rc3","v1.13.0-rc2","v1.13.0-rc1","zephyr-v1.12.0","v1.12.0","v1.12.0-rc3","v1.12.0-rc2","v1.12.0-rc1","zephyr-v1.11.0","v1.11.0","v1.11.0-rc3","v1.11.0-rc2","v1.11.0-rc1","zephyr-v1.10.0","v1.10.0","v1.10.0-rc3","v1.10.0-rc2","v1.10.0-rc1","zephyr-v1.9.0","v1.9.0","v1.9.0-rc4","v1.9.0-rc3","v1.9.0-rc2","v1.9.0-rc1","v1.8.99","zephyr-v1.5.0","v1.5.0","v1.7.99","v1.6.99","v1.5.0-rc4","v1.5.0-rc3","v1.5.0-rc2","v1.5.0-rc1","v1.5.0-rc0","zephyr-v1.4.0","v1.4.0","v1.4.0-rc3","v1.4.0-rc2","v1.4.0-rc1","zephyr-v1.3.0","v1.3.0","v1.3.0-rc2","v1.3.0-rc1","zephyr-v1.2.0","v1.2.0","v1.2.0-rc2","v1.2.0-rc1","zephyr-v1.1.0","v1.1.0","v1.1.0-rc1","zephyr-v1.0.0","v1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-19737.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}