{"id":"CVE-2026-9771","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-9771","summary":"The flash_copy() system call is verified by z_vrfy_flash_copy() in drivers/flash/flash_util.c. On builds with CONFIG_USERSPACE enabled, this handler is the kernel-side trust boundary…","details":"The flash_copy() system call is verified by z_vrfy_flash_copy() in drivers/flash/flash_util.c. On builds with CONFIG_USERSPACE enabled, this handler is the kernel-side trust boundary for a user-mode caller. Prior to the fix it validated only the output buffer (K_SYSCALL_MEMORY_WRITE) and passed the two struct device * arguments, src_dev and dst_dev, directly into the implementation without any object validation — unlike every sibling flash syscall, which guards its device pointer with K_SYSCALL_DRIVER_FLASH.\n\nA user-mode thread fully controls the values of src_dev/dst_dev and the contents of its own address space. The implementation z_impl_flash_copy() dereferences these pointers and calls through their driver-API function tables (e.g. api->get_parameters(dst_dev), flash_read(src_dev, ...), flash_write(dst_dev, ...)). By supplying a pointer to a forged struct device whose api table contains attacker-chosen function pointers, an unprivileged thread can cause the kernel to call arbitrary code in supervisor mode; passing any arbitrary or invalid address otherwise yields a kernel crash or out-of-bounds read.\n\nThe result is a local privilege escalation out of the userspace sandbox (with kernel denial-of-service and information disclosure as lesser outcomes). The fix adds K_SYSCALL_DRIVER_FLASH(src_dev, read) and K_SYSCALL_DRIVER_FLASH(dst_dev, write) to z_vrfy_flash_copy(), which verify each device is a registered flash-driver kernel object the calling thread is permitted to use before any dereference, closing the path completely.","published":"2026-08-17T17:16:57.720","modified":"2026-08-17T17:16:57.720","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/1b1ecdc438092cdd469319a0d51cba6cf82e06f4","label":"zephyrproject-rtos/zephyr@1b1ecdc"},"references":[{"type":"WEB","url":"https://github.com/zephyrproject-rtos/zephyr/commit/1b1ecdc438092cdd469319a0d51cba6cf82e06f4"},{"type":"WEB","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-68cj-3hg4-5vpm"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-17T17:16:57.720"}}