CVE-2026-64277
In the Linux kernel, the following vulnerability has been resolved:
Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count
rmi_f3a_initialize() takes the GPIO count from the device query register
(f3a->gpio_count = buf & RMI_F3A_GPIO_COUNT, range 0..127).
rmi_f3a_map_gpios() then allocates gpio_key_map with
min(gpio_count, TRACKSTICK_RANGE_END) == at most 6 entries, but
rmi_f3a_attention() iterates the full gpio_count and dereferences
gpio_key_map[i], and input->keycodemax is set to the full gpio_count
while input->keycode points at the 6-entry allocation.
A device that reports gpio_count > 6 therefore causes an out-of-bounds
read of gpio_key_map[] on every attention interrupt, and out-of-bounds
accesses through the input core's default keymap ioctls: EVIOCGKEYCODE
reads past the buffer (leaking adjacent slab memory to user space) and
EVIOCSKEYCODE writes a caller-controlled value past it, for any process
able to open the evdev node, since input_default_getkeycode() and
input_default_setkeycode() only bound the index against keycodemax.
Size the keymap for the full gpio_count. The mapping loop is unchanged:
it still assigns only the first min(gpio_count, TRACKSTICK_RANGE_END)
entries; the remaining slots stay KEY_RESERVED (devm_kcalloc zero-fills)
and are skipped when reporting.
CSIRTS triage
- What
- This vulnerability bounds the F3A keymap to the GPIO count.
- Who is affected
- Deployments using the synaptics-rmi4 input driver.
- Urgency
- Remediation is important to ensure proper functionality, although no exploitation has been reported.
- Action
- Apply the patch for CVE-2026-64277.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.16% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
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