139 lines
7.2 KiB
JSON
139 lines
7.2 KiB
JSON
{
|
|
"dataType": "CVE_RECORD",
|
|
"dataVersion": "5.2",
|
|
"cveMetadata": {
|
|
"cveId": "CVE-2026-90834",
|
|
"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
|
|
"state": "PUBLISHED",
|
|
"assignerShortName": "zephyr",
|
|
"dateReserved": "2026-09-13T19:23:00.663Z",
|
|
"datePublished": "2026-11-10T22:07:45.167Z",
|
|
"dateUpdated": "2026-11-13T13:34:49.079Z"
|
|
},
|
|
"containers": {
|
|
"cna": {
|
|
"providerMetadata": {
|
|
"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
|
|
"shortName": "zephyr",
|
|
"dateUpdated": "2026-11-10T22:07:45.167Z"
|
|
},
|
|
"title": "UART wide-data syscall verifiers check the 8-bit driver op, allowing a user-mode thread to trigger a NULL function-pointer call in kernel mode",
|
|
"descriptions": [
|
|
{
|
|
"lang": "en",
|
|
"value": "The user-mode syscall verifiers for the 16-bit (\"wide data\") UART API in drivers/serial/uart_handlers.c validated the wrong driver operation. z_vrfy_uart_poll_out_u16(), z_vrfy_uart_tx_u16() and z_vrfy_uart_rx_enable_u16() each ran K_SYSCALL_DRIVER_UART() against the 8-bit op (poll_out, tx, rx_enable) rather than the 16-bit op that the corresponding implementation dereferences (poll_out_u16, tx_u16, rx_enable_u16). z_impl_uart_poll_out_u16(), z_impl_uart_tx_u16() and z_impl_uart_rx_enable_u16() in include/zephyr/drivers/uart/uart_internal.h call their op unconditionally, with no NULL guard of their own, because the verifier is supposed to have established that the op exists.\n\nCONFIG_UART_WIDE_DATA is an application-selectable option that no driver selects, and only a handful of the serial drivers in the tree implement any _u16 operation; every other driver leaves those struct uart_driver_api members NULL while still providing the 8-bit ops the old check inspected. In a build with CONFIG_USERSPACE and CONFIG_UART_WIDE_DATA (plus CONFIG_UART_ASYNC_API for the uart_tx_u16() and uart_rx_enable_u16() variants), an unprivileged user-mode thread that legitimately holds access to such a UART device object can invoke the _u16 syscall: the object, permission and op checks all pass, and the kernel-side implementation then performs an indirect call through a NULL function pointer while running at supervisor privilege.\n\nThe result is a CPU exception taken in kernel context instead of the intended K_OOPS or -ENOSYS return. With the default k_sys_fatal_error_handler() this halts the system (or warm-reboots it under CONFIG_RESET_ON_FATAL_ERROR), so a thread confined by the userspace sandbox can deny service to the whole device — a capability the user-mode privilege boundary is specifically meant to withhold. The call target is a fixed NULL, so there is no attacker-controlled code execution and no memory disclosure; the separate K_SYSCALL_MEMORY_ARRAY_READ()/K_SYSCALL_MEMORY_ARRAY_WRITE() bounds checks on the caller's buffer were and remain correct. The fix points each verifier at the matching _u16 op, using a plain K_SYSCALL_OBJ() object check where the op does not exist or where the implementation already tests it for NULL."
|
|
}
|
|
],
|
|
"affected": [
|
|
{
|
|
"vendor": "zephyrproject",
|
|
"product": "zephyr",
|
|
"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
|
|
"packageName": "zephyr",
|
|
"defaultStatus": "unaffected",
|
|
"programFiles": [
|
|
"drivers/serial/uart_handlers.c"
|
|
],
|
|
"programRoutines": [
|
|
{
|
|
"name": "z_vrfy_uart_poll_out_u16"
|
|
},
|
|
{
|
|
"name": "z_vrfy_uart_rx_enable_u16"
|
|
},
|
|
{
|
|
"name": "z_vrfy_uart_tx_u16"
|
|
}
|
|
],
|
|
"versions": [
|
|
{
|
|
"version": "3.0.0",
|
|
"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/3c13bfd3d3ccdceeb51b884fed5a8d2a49475484",
|
|
"name": "Fix commit",
|
|
"tags": [
|
|
"patch"
|
|
]
|
|
},
|
|
{
|
|
"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-xvwx-ww79-r346",
|
|
"name": "GHSA-xvwx-ww79-r346"
|
|
}
|
|
],
|
|
"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": "2026-11-13T13:34:36.820599Z",
|
|
"id": "CVE-2026-90834",
|
|
"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": "2026-11-13T13:34:49.079Z"
|
|
}
|
|
}
|
|
]
|
|
}
|
|
} |