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vuln-cve/data/2026/19xxx/CVE-2026-19185.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-19185",
"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
"state": "PUBLISHED",
"assignerShortName": "zephyr",
"dateReserved": "2026-08-06T18:36:11.738Z",
"datePublished": "2026-10-05T08:06:29.874Z",
"dateUpdated": "2026-11-04T05:00:33.963Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
"shortName": "zephyr",
"dateUpdated": "2026-11-04T05:00:33.963Z"
},
"title": "Unvalidated user-supplied buffer pointers in the I3C do_ccc system call handler allow kernel memory read/write from user mode",
"descriptions": [
{
"lang": "en",
"value": "The system-call verifier for i3c_do_ccc() in drivers/i3c/i3c_handlers.c validated the outer struct i3c_ccc_payload, the broadcast ccc.data buffer and the targets.payloads[] array, but did not validate the per-target data buffers those array elements point at. Each struct i3c_ccc_target_payload carries its own data pointer and data_len, and neither was passed through K_SYSCALL_MEMORY() before the payload was handed to z_impl_i3c_do_ccc() and on to the controller driver. The verifier also operated on the caller's live structure rather than a snapshot, so validated fields could be changed by a second user thread between the check and the driver's use — unlike the sibling z_vrfy_i3c_transfer(), which has always copied its message array first.\n\nThe defect is only present in CONFIG_USERSPACE builds, where drivers/i3c/i3c_handlers.c is compiled. An unprivileged user-mode thread that has been granted access to the I3C controller device object — the ordinary way an application lets a user thread talk to I3C peripherals — can issue a direct CCC whose target payload data pointer names an arbitrary kernel address. Controller drivers dereference that pointer directly (for example drivers/i3c/i3c_mcux.c, drivers/i3c/i3c_cdns.c, drivers/i3c/i3c_stm32.c, drivers/i3c/i3c_npcx.c), using rnw to decide direction.\n\nA read CCC therefore causes the kernel-mode driver to write bus-received bytes into an attacker-chosen kernel address for an attacker-chosen length, and a write CCC transmits kernel memory out onto the I3C bus. The result is an out-of-bounds kernel write plus a kernel memory disclosure, i.e. escalation from a user-mode thread to supervisor privilege, defeating the isolation CONFIG_USERSPACE is meant to provide.\n\nThe fix introduces copy_ccc_and_do(), which snapshots the payload, copies the target array into kernel memory with k_usermode_alloc_from_copy() (bounding num_targets to fewer than 32), validates each per-target buffer with K_SYSCALL_MEMORY() according to rnw, and copies the driver-written num_xfer and err fields back to the caller."
}
],
"affected": [
{
"vendor": "zephyrproject",
"product": "zephyr",
"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
"packageName": "zephyr",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/i3c/i3c_handlers.c"
],
"programRoutines": [
{
"name": "z_vrfy_i3c_do_ccc"
}
],
"versions": [
{
"version": "3.2.0",
"status": "affected",
"versionType": "semver",
"lessThan": "4.3.2"
},
{
"version": "4.4.0",
"status": "affected",
"versionType": "semver",
"lessThan": "4.5.0"
}
]
}
],
"references": [
{
"url": "https://github.com/zephyrproject-rtos/zephyr/commit/35562f22f40c6d2f31969a31f0a4902e5b067f27",
"name": "Fix commit",
"tags": [
"patch"
]
},
{
"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-pcrr-29j7-8w57",
"name": "GHSA-pcrr-29j7-8w57"
}
],
"metrics": [
{
"format": "CVSS",
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"description": "memory-safety",
"cweId": "CWE-822",
"type": "CWE"
}
]
}
],
"x_generator": {
"engine": "cvelib 1.8.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"timestamp": "2026-10-05T14:06:01.294641Z",
"id": "CVE-2026-19185",
"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": "2026-10-05T14:06:55.566Z"
}
}
]
}
}