140 lines
7.5 KiB
JSON
140 lines
7.5 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-19595",
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"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
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"state": "PUBLISHED",
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"assignerShortName": "zephyr",
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"dateReserved": "2026-08-12T05:34:36.022Z",
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"datePublished": "2026-10-19T22:49:40.334Z",
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"dateUpdated": "2026-11-04T05:01:16.762Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
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"shortName": "zephyr",
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"dateUpdated": "2026-11-04T05:01:16.762Z"
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},
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"title": "Zephyr RTIO syscall verifier validates output parameters for read instead of write access",
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"descriptions": [
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{
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"lang": "en",
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"value": "The user-mode syscall verifier z_vrfy_rtio_cqe_get_mempool_buffer() in subsys/rtio/rtio_syscalls.c validated its two output parameters, buff and buff_len, with K_SYSCALL_MEMORY_READ() rather than K_SYSCALL_MEMORY_WRITE(). Both are pure out-parameters: z_impl_rtio_cqe_get_mempool_buffer() stores the mempool buffer address and its length through them. The distinction is enforced by every architecture validator — arch_buffer_validate() on RISC-V PMP explicitly accepts the global __rom_region/__rodata_region for reads only, and the ARM MPU validators accept P_RO_U_RO and P_RW_U_RO regions for reads only — so a read-validated pointer is not necessarily writable by the calling thread.\n\nAn unprivileged user-mode thread that has been granted access to an RTIO context (rtio_access_grant()) can invoke the rtio_cqe_get_mempool_buffer() syscall with buff/buff_len pointing at memory it may read but not write, and with a completion-queue entry whose flags field it fully controls (only RTIO_CQE_FLAG_MEMPOOL_BUFFER in flags[7:0] is required; flags[19:8] and flags[31:20] supply the block index and count). The kernel then performs a pointer-sized and a 4-byte store through those addresses while running in supervisor mode. Reaching the store requires CONFIG_USERSPACE together with CONFIG_RTIO_SYS_MEM_BLOCKS, the configuration behind RTIO_DEFINE_WITH_MEMPOOL; without the latter the implementation returns -ENOTSUP and writes nothing.\n\nTwo outcomes follow. If the target lies in a memory-domain partition declared K_MEM_PARTITION_P_RW_U_RO (privileged read-write, user read-only), the kernel-mode store succeeds and deposits partly attacker-chosen values into memory the memory domain had marked read-only for that thread, bypassing the partition's write protection. If the target lies in globally readable but unwritable memory such as .text/.rodata in flash, the store faults in kernel mode; the fault is delivered to z_fatal_error() and the default k_sys_fatal_error_handler() halts or reboots the device, giving an unprivileged thread a reliable full denial of service.\n\nThe read-permission check does bound the damage: the address must still be readable by the calling thread, so kernel-private memory cannot be targeted and no confidential data is disclosed. The fix replaces both checks with K_SYSCALL_MEMORY_WRITE(), so a thread lacking write permission is terminated by K_OOPS before the implementation runs; the cqe argument correctly remains read-validated."
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}
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],
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"affected": [
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{
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"vendor": "zephyrproject",
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"product": "zephyr",
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"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
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"packageName": "zephyr",
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"defaultStatus": "unaffected",
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"programFiles": [
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"subsys/rtio/rtio_handlers.c",
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"subsys/rtio/rtio_syscalls.c"
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],
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"programRoutines": [
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{
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"name": "z_vrfy_rtio_cqe_get_mempool_buffer"
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}
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],
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"versions": [
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{
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"version": "3.4.0",
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"status": "affected",
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"versionType": "semver",
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"lessThan": "4.3.2"
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},
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{
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"version": "4.4.0",
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"status": "affected",
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"versionType": "semver",
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"lessThan": "4.5.0"
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}
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]
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}
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],
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"references": [
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/commit/bea93400138362691403b7f81de1e9048681547d",
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"name": "Fix commit",
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"tags": [
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"patch"
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]
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},
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7337-mc44-5wjm",
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"name": "GHSA-7337-mc44-5wjm"
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}
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],
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"metrics": [
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{
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"format": "CVSS",
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H",
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"baseScore": 6.1,
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"baseSeverity": "MEDIUM"
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}
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}
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],
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"problemTypes": [
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{
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"descriptions": [
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{
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"lang": "en",
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"description": "memory-safety",
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"cweId": "CWE-787",
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"type": "CWE"
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},
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{
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"lang": "en",
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"description": "memory-safety",
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"cweId": "CWE-822",
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"type": "CWE"
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}
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]
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}
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],
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"x_generator": {
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"engine": "cvelib 1.8.0"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"timestamp": "2026-10-20T19:21:33.416588Z",
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"id": "CVE-2026-19595",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "partial"
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}
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],
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"role": "CISA Coordinator",
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"version": "2.0.3"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-10-20T19:21:46.367Z"
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}
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}
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]
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}
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} |