📌 이 취약점에 대해 확인된 사실
전부 발행처가 발표한 값입니다. 우리가 계산하거나 판단한 숫자는 하나도 없습니다.
악용 여부
심각도 (발행처 발표값)
보통4.4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
악용 확률 (EPSS)
0.1%
📄 원문 그대로
아래 문장은 전부 발행처가 쓴 것입니다. 번역하지 않습니다 — 보안 문서의 오역은 조치를 바꿉니다.
취약점 설명 (NVD)
The SMBus driver API exposed smbus_smbalert_remove_cb() and smbus_host_notify_remove_cb() as Zephyr syscalls. Their verifiers in drivers/smbus/smbus_handlers.c validated only the dev argument with K_SYSCALL_OBJ(dev, K_OBJ_DRIVER_SMBUS) and forwarded the caller-supplied struct smbus_callback *cb pointer into kernel-mode driver code without any K_SYSCALL_MEMORY_READ/K_SYSCALL_MEMORY_WRITE validation. A companion change in 2023 had already removed the matching smbus_smbalert_set_cb() / smbus_host_notify_set_cb() syscalls for this reason, but the two removal syscalls were left exposed. On a build with CONFIG_USERSPACE=y, CONFIG_SMBUS=y and a driver implementing the callback operations (drivers/smbus/intel_pch_smbus.c with CONFIG_SMBUS_INTEL_PCH_SMBALERT/CONFIG_SMBUS_INTEL_PCH_HOST_NOTIFY, or drivers/smbus/smbus_stm32.c with CONFIG_SMBUS_STM32_SMBALERT), any user-mode thread that has been granted the SMBus device object can invoke these syscalls with an arbitrary pointer. The value reaches smbus_callback_remove() in drivers/smbus/smbus_utils.h, which uses it as a node identity against the kernel's sys_slist_t of registered callbacks. The consequence is that an unprivileged thread can unregister an SMBALERT or Host Notify callback that a supervisor-mode component registered, silently disabling alert handling for the rest of the system; because Zephyr images have fixed symbol addresses and the syscall returns 0 on a hit versus -ENOENT on a miss, the target address is both derivable and searchable. In builds with CONFIG_ASSERT=y the __ASSERT(callback->handler, ...) check additionally dereferences the caller-supplied address in supervisor mode, so a bogus pointer raises a kernel-mode fault and a fatal system error, and the fault/no-fault outcome discloses which addresses are mapped. The fix removes both syscall entry points, demoting the two functions to ordinary static inline calls so that callback list manipulation is available only to supervisor-mode code. There is no impact on builds without CONFIG_USERSPACE, and no impact on configurations that do not enable an SMBus driver with SMBALERT or Host Notify support.
참고
악용 확률 변화
우리가 매일 저장한 EPSS 스냅샷입니다. 원본은 전날 값만 주므로, 이 표는 수집을 시작한 이후만 보여줍니다.
| 기준일 | 확률 | 백분위 |
|---|---|---|
| 2026-10-04 | 0.09% | 0.4% |
| 2026-10-03 | 0.09% | 0.4% |
| 2026-10-02 | 0.09% | 0.4% |
🧩 같은 약점 유형 — CWE-862
같은 분류의 다른 취약점입니다. 같은 실수가 제품을 가리지 않고 반복됩니다.