{"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": "2026-10-05T08:06:29.874Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad", "shortName": "zephyr", "dateUpdated": "2026-10-05T08:06:29.874Z"}, "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 \u2014 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 \u2014 the ordinary way an application lets a user thread talk to I3C peripherals \u2014 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", "lessThan": "4.5.0", "versionType": "semver"}]}], "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"}}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://github.com/zephyrproject-rtos/zephyr", "defaultStatus": "unaffected", "packageName": "zephyr", "product": "zephyr", "programFiles": ["drivers/i3c/i3c_handlers.c"], "programRoutines": [{"name": "z_vrfy_i3c_do_ccc"}], "vendor": "zephyrproject", "versions": [{"lessThan": "4.5.0", "status": "affected", "version": "3.2.0", "versionType": "semver"}]}], "source": "vulnerabilities@zephyrproject.org"}], "cveTags": [], "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 \u2014 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 \u2014 the ordinary way an application lets a user thread talk to I3C peripherals \u2014 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."}], "id": "CVE-2026-19185", "lastModified": "2026-10-05T09:17:13.077", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "vulnerabilities@zephyrproject.org", "type": "Secondary"}]}, "published": "2026-10-05T09:17:13.077", "references": [{"source": "vulnerabilities@zephyrproject.org", "url": "https://github.com/zephyrproject-rtos/zephyr/commit/35562f22f40c6d2f31969a31f0a4902e5b067f27"}, {"source": "vulnerabilities@zephyrproject.org", "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-pcrr-29j7-8w57"}], "sourceIdentifier": "vulnerabilities@zephyrproject.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-822"}], "source": "vulnerabilities@zephyrproject.org", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.2.0,4.5.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "zephyr", "source": "cna", "vendor": "zephyrproject"}, "product": "zephyr", "vendor": "zephyrproject"}], "created": "2026-10-05T09:30:09.905550+00:00", "updated": "2026-10-05T09:30:10.640723+00:00", "vendors": ["zephyrproject", "zephyrproject$PRODUCT$zephyr"]}