CVE-2026-19576 Escritura fuera de límites en la pila del driver Goodix GT911 por conteo de puntos no validado
El driver lee el conteo de puntos táctiles del registro de estado del controlador (0 a 15) y lo usa como límite del bucle que llena point_reg[], un array de pila dimensionado por CONFIG_INPUT_GT911_MAX_TOUCH_POINTS (1 a 5). Un controlador que reporte más puntos de los configurados escribe hasta 112 bytes de datos por I2C más allá del array, sobre la pila del hilo de workqueue del sistema.
CVSS 3.1
- Probabilidad de explotación0,2 %
- Explotada activamenteNo confirmada
- Exploit públicoNo conocido
Afectados
zephyrproject zephyr
desde 4.0.0 hasta 4.4.2
Qué hacer
- Verificá si usás zephyr y en qué versión.
- Actualizá a la versión corregida que indique el fabricante en su aviso o aplicá su mitigación.
- Revisá registros y accesos de los sistemas expuestos para descartar un uso previo.
Calculadora CVSS
CVSS 3.1 · 6.8 MEDIA
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Vector de ataqueFísico
- Complejidad del ataqueBaja
- Privilegios requeridosNinguno
- Interacción del usuarioNinguna
- AlcanceSin cambio
- ConfidencialidadAlta
- IntegridadAlta
- DisponibilidadAlta
Descripción original
The Goodix GT9xx input driver in drivers/input/input_gt911.c reads the touch point count from the controller's status register and masks it with GT911_TOUCH_POINTS_MSK (0x0F), yielding a value of 0..15. In gt911_process() that value is used directly as the loop bound for filling point_reg[], a stack array sized to CONFIG_INPUT_GT911_MAX_TOUCH_POINTS, whose Kconfig range is 1..5 with a default of 1. No other check constrains the count; the driver relied only on a comment asserting that the controller had been programmed at init to report no more points than configured.
Each loop iteration issues an I2C read of eight bytes straight into point_reg[i], so a controller that reports more points than the array holds causes up to 112 bytes of peer-supplied data to be written past the end of the array, over the stack frame of gt911_process() in the system workqueue thread. Two further loops then read out of bounds from the same array. Triggering it requires control of, or the ability to substitute, the I2C touch controller — plausible on the many supported boards where the GT9xx panel is a pluggable display module or shield rather than an on-PCB part; a spoofed device need only answer the init probes with a supported product ID and a checksum-valid config blob. The same overflow can also occur non-adversarially, with a GT9271-class panel that ignores the driver's touch-count programming and reports up to ten points, or with bus corruption of the single status byte.
The impact is an out-of-bounds stack write with fully attacker-chosen content executing at kernel privilege, i.e. potential control-flow hijack on the host MCU, in addition to out-of-bounds reads and crashes. The attack vector is physical/local hardware access only; there is no network, USB, or syscall path to the defect. The fix clamps the reported count with min() against CONFIG_INPUT_GT911_MAX_TOUCH_POINTS before any array indexing.
Referencias (2)
Resumen traducido automáticamente de la descripción original. Fuente: Nureq Monitor. Cómo funciona.