{"apiVersion":"1.0","identifier":"CVE-2026-9771","description":"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. A 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. The 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.","publishedAt":"2026-08-17T17:16:57","lastModifiedAt":"2026-08-26T16:59:23","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-9771","cvssScore":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","epssProbability":0.00106,"riskScore":0.89,"affectedProduct":"Zephyr","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-9771","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-9771","en":"https://www.redsauce.net/en/cves/CVE-2026-9771","fr":"https://www.redsauce.net/fr/cves/CVE-2026-9771","pt":"https://www.redsauce.net/pt/cves/CVE-2026-9771","de":"https://www.redsauce.net/de/cves/CVE-2026-9771","sk":"https://www.redsauce.net/sk/cves/CVE-2026-9771","el":"https://www.redsauce.net/el/cves/CVE-2026-9771"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-9771"}}