{"id":"CVE-2026-17052","published":"2026-09-21T19:17:04.080","lastModified":"2026-09-21T19:17:04.080","description":"The Time-aware GPIO syscall verification handler z_vrfy_tgpio_pin_read_ts_ec() in drivers/timeaware_gpio/timeaware_gpio_handlers.c validated only the port device object and passed the caller-supplied timestamp and event_count output pointers to the driver without a K_SYSCALL_MEMORY_WRITE() check. The other handlers in the same file (z_vrfy_tgpio_port_get_time(), z_vrfy_tgpio_port_get_cycles_per_second()) already performed that check, so the omission left one syscall unguarded.\n\ntgpio_pin_read_ts_ec() is declared __syscall, so with CONFIG_USERSPACE=y an unprivileged user-mode thread that has been granted access to the TGPIO device object can invoke it with arbitrary pointer values. tgpio_intel_read_ts_ec() in drivers/timeaware_gpio/timeaware_gpio_intel.c bounds-checks only the pin index and then unconditionally performs timestamp = ... and event_count = ..., executing two 8-byte stores in supervisor mode at addresses chosen by the user-mode caller.\n\nThe result is a write-what-where primitive that crosses the userspace/kernel boundary: the target address is fully attacker-chosen and the stored values are the hardware time-capture and event-counter register contents. Corrupting kernel data structures this way can escalate the calling thread to supervisor privilege or crash the system; the device-object permission required is a narrow capability that is not intended to confer any kernel-memory access. The fix adds the two missing K_SYSCALL_MEMORY_WRITE() validations before the driver call.\n\nExposure is narrow in practice. Only builds with CONFIG_USERSPACE=y and CONFIG_TIMEAWARE_GPIO=y compile the affected file, and from v3.6.0 onward the file additionally referenced a relocated header (<zephyr/syscall_handler.h>) and removed Z_SYSCALL_* macros, so such a configuration failed to build until those were repaired after v4.4.0. Downstream trees that locally corrected that breakage, and v3.5.0 builds where it did not exist, are the exposed population.","cvssScore":7.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-787"],"vendors":[],"products":[],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/26264fffc17c2174319394ffa274af3f6efdc221","tags":[]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8qw6-x76h-8mpc","tags":[]}],"exploitRefs":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/26264fffc17c2174319394ffa274af3f6efdc221","tags":[]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8qw6-x76h-8mpc","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw allows an unprivileged user to write arbitrary values to kernel memory through a syscall, potentially leading to privilege escalation or system crashes.","exploitability":"Exploitation requires access to the TGPIO device object and CONFIG_USERSPACE=y; moderate difficulty due to specific conditions.","blast_radius":"Impact is high if exploited, as it can lead to full system compromise or kernel crashes.","remediation":"Update affected kernel versions to patches that include proper K_SYSCALL_MEMORY_WRITE() checks.","tags":["rce","kernel","privilege-escalation","memory-write"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-22T06:09:55.109Z"}}