CVE-2026-10669— zephyrproject zephyr 缓冲区错误漏洞

Xtensa MPU `arch_buffer_validate()` integer-overflow lets a user thread bypass syscall pointer validation

On Xtensa SoCs built with CONFIG_XTENSA_MPU and CONFIG_USERSPACE, arch_buffer_validate() in arch/xtensa/core/mpu.c — the architecture hook that verifies a user-mode-supplied buffer is accessible to the calling user thread with the requested permission — defaulted its return value to 0 (access permitted) and only set a denial result inside its per-MPU-region probe loop. When the rounded extent of the buffer wraps the 32-bit address space (size + alignment offset near SIZE_MAX, or ROUND_UP(size + offset) overflowing to 0), the loop executes zero iterations and the function returns 0 = permitted without probing any MPU region. The syscall-layer pre-checks (K_SYSCALL_MEMORY_SIZE_CHECK / Z_DETECT_POINTER_OVERFLOW) only catch a raw addr+size wrap and do not cover the ROUND_UP-induced wrap, and the string path (arch_user_string_nlen -> arch_buffer_validate) has no syscall-layer guard at all. An unprivileged user-mode thread can therefore pass a crafted (addr, size) to any syscall that validates user buffers via k_usermode_from_copy/to_copy or k_usermode_string_copy and have validation succeed for memory it must not access; the kernel then reads from (disclosure) or, with write=1, writes to (corruption) attacker-chosen kernel or other-partition memory on the thread's behalf, enabling information disclosure, memory corruption, privilege escalation, and denial of service. Affected from v3.7.0 (when Xtensa MPU userspace support was added) through v4.4.0. The fix changes the default to -EINVAL (deny by default), adds an explicit size_add_overflow check, and sets the success value only after the full range has been validated.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

跨界内存写

zephyrproject zephyr 缓冲区错误漏洞

zephyrproject zephyr是zephyrproject组织开源的一款实时操作系统内核。 zephyr 3.7.0版本至4.4.0版本存在缓冲区错误漏洞，该漏洞源于arch_buffer_validate()函数默认返回值为0（允许访问），当缓冲区范围环绕32位地址空间时，导致MPU区域探测循环执行零次并返回允许访问，未授权用户模式线程可通过特制地址和大小参数绕过验证，导致信息泄露、内存破坏、权限提升和拒绝服务。

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