CVE-2026-17052

7.8 HIGHpublic exploit available

Published 2026-09-21 · Updated 2026-09-21

AI risk analysis

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.
Prioritized remediation: Update affected kernel versions to patches that include proper K_SYSCALL_MEMORY_WRITE() checks.

rcekernelprivilege-escalationmemory-write

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD 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. tgpio_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. The 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. Exposure 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.

CVSS vector

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

Weaknesses

CWE-787

Public exploit & PoC references

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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