{"id":"CVE-2026-19737","revision":"74c8fc0407eb47c481eab78ca832687d","records":[{"revision":"74c8fc0407eb47c481eab78ca832687d","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-19737","aliases":[],"title":"NULL pointer dereference in the ESP32 I2S driver when triggering an unsupported direction","description":"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->rx.data->configured / dev_cfg->tx.data->configured 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.","state":0,"publishedAt":"2026-10-11T17:15:01.878+00:00","modifiedAt":"2026-10-16T15:46:16.4+00:00","affected":[{"ecosystem":"https://github.com/zephyrproject-rtos/zephyr","name":"zephyr","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"zephyrproject\",\n                    \"product\": \"zephyr\",\n                    \"collectionURL\": \"https://github.com/zephyrproject-rtos/zephyr\",\n                    \"packageName\": \"zephyr\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"programFiles\": [\n                        \"drivers/i2s/i2s_esp32.c\"\n                    ],\n                    \"programRoutines\": [\n                        {\n                            \"name\": \"i2s_esp32_trigger\"\n                        },\n                        {\n                            \"name\": \"i2s_esp32_trigger_check\"\n                        }\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.4.0\",\n                            \"status\": \"affected\",\n                            \"lessThan\": \"4.5.0\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5,"severity":"MEDIUM"}],"references":["https://github.com/zephyrproject-rtos/zephyr/commit/0d82dbbe72f154de32cc45021a9f59d9a737246b","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-5g9q-h8wq-rrf3"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-19737","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-19737","identifiers":["CVE-2026-19737"]},"retained":false,"historicalAffected":[]}],"coverage":[]}