{"schema":"threatline.record/2","record":{"id":"CVE-2026-82961","aliases":["GHSA-4f2x-8qw8-jjgf"],"summary":"Unvalidated pin index in GPIO syscall handlers allows out-of-bounds kernel writes from user mode","details":"The GPIO syscall handlers in drivers/gpio/gpio_handlers.c did not validate the pin argument supplied by a user-mode caller. z_vrfy_gpio_pin_configure(), z_vrfy_gpio_pin_get_config() and z_vrfy_gpio_pin_interrupt_configure() verified only the device object (K_SYSCALL_DRIVER_GPIO() / K_SYSCALL_OBJ()) and then passed the caller-supplied gpio_pin_t straight through to z_impl_gpio_pin_*() and on to the driver. The only pin check in include/zephyr/drivers/gpio.h was __ASSERT(gpio_port_pin_is_supported(cfg->port_pin_mask, pin), ...), which compiles to nothing unless CONFIG_ASSERT is enabled, so in a production build no check existed at all.\n\nGPIO drivers use pin as a shift count and as an array index on the documented assumption that it is a pin the controller supports. On STM32, for example, gpio_stm32_pin_interrupt_configure() turns pin into an EXTI line and stm32_gpio_intc_set_irq_callback() writes data->cb[line_num].cb and data->cb[line_num].data into a NUM_EXTI_LINES-entry array (default 16) in drivers/interrupt_controller/intc_gpio_stm32.c, guarded only by a compiled-out __ASSERT_NO_MSG(); the same function then reads exti_irq_table[line_num] and calls irq_enable() on the result. Other controllers index fixed-size per-pin configuration tables the same way — drivers/gpio/gpio_ite_it8xxx2_v2.c reads an MMIO base pointer out of wuc_base[8] with the caller's pin and performs a read-modify-write through it.\n\nThe issue is reachable only in builds with CONFIG_USERSPACE=y (the file is compiled under that symbol), by a user-mode thread that has been granted access to a GPIO device object. Such a grant is intended to authorize control of that port's pins; the missing validation instead lets the thread drive a supervisor-mode out-of-bounds write of a function pointer and an associated void * past a kernel .bss array, and out-of-bounds reads that feed irq_enable() and MMIO accesses — an escape from the user-mode sandbox that can lead to kernel memory corruption, arbitrary code execution, or a crash.\n\nThe fix validates pin against the controller's gpio_driver_config.port_pin_mask with gpio_port_pin_is_supported() in every pin-taking z_vrfy_ handler and returns -EINVAL otherwise, complemented by an unconditional pin >= GPIO_MAX_PINS_PER_PORT range check added to the shared z_impl_gpio_pin_*() inlines.","categories":["Unclassified"],"product":"zephyr","vendor":"zephyrproject","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-82961","source_modified_at":"2026-10-28T16:58:58.927Z","fetched_at":"2026-10-28T20:58:01.013507Z","product":"zephyr","vendor":"zephyrproject","versions":[{"version":"2.2.0","status":"affected","versionType":"semver","lessThanOrEqual":"4.4.2"}],"defaultStatus":"unaffected"}],"fixed_versions":[],"cvss":7.8,"severity":"High","kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-28T16:58:58.927Z","modified_at":"2026-10-28T16:58:58.927Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-82961","fetched_at":"2026-10-28T20:58:01.013507Z","source_modified_at":"2026-10-28T16:58:58.927Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/commit/020e83e06b35e98a4a3c2354f67e5eee3f163363","tags":["patch"]},{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/commit/d145faab7e3a8cea62a8fd7ed5f30ef73e762f59","tags":["patch"]},{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/commit/c9641fa5bfec44892e0cf2d84f78c7c60fca8ad6","tags":["patch"]},{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/commit/d28a05d5de4420f27ba3de7b9e4442fa056d51de","tags":["patch"]},{"source":"CVE List","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4f2x-8qw8-jjgf"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-28T16:58:58.927Z","content_hash":"c0ac54a8e5c13cc0960afb2e1d9231bd1adba09aa547e067010779fcf06664b3"}}