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vuln-cve/data/2026/19xxx/CVE-2026-19737.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-19737",
"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
"state": "PUBLISHED",
"assignerShortName": "zephyr",
"dateReserved": "2026-08-13T13:46:28.028Z",
"datePublished": "2026-10-11T17:15:01.878Z",
"dateUpdated": "2026-10-16T15:46:16.400Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
"shortName": "zephyr",
"dateUpdated": "2026-10-11T17:15:01.878Z"
},
"title": "NULL pointer dereference in the ESP32 I2S driver when triggering an unsupported direction",
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"affected": [
{
"vendor": "zephyrproject",
"product": "zephyr",
"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
"packageName": "zephyr",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/i2s/i2s_esp32.c"
],
"programRoutines": [
{
"name": "i2s_esp32_trigger"
},
{
"name": "i2s_esp32_trigger_check"
}
],
"versions": [
{
"version": "4.4.0",
"status": "affected",
"lessThan": "4.5.0",
"versionType": "semver"
}
]
}
],
"references": [
{
"url": "https://github.com/zephyrproject-rtos/zephyr/commit/0d82dbbe72f154de32cc45021a9f59d9a737246b",
"name": "Fix commit",
"tags": [
"patch"
]
},
{
"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-5g9q-h8wq-rrf3",
"name": "GHSA-5g9q-h8wq-rrf3"
}
],
"metrics": [
{
"format": "CVSS",
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"baseScore": 5.5,
"baseSeverity": "MEDIUM"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"description": "memory-safety",
"cweId": "CWE-476",
"type": "CWE"
}
]
}
],
"x_generator": {
"engine": "cvelib 1.8.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"timestamp": "2026-10-16T15:45:22.302843Z",
"id": "CVE-2026-19737",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-10-16T15:46:16.400Z"
}
}
]
}
}