CVE-2026-80768

In the Linux kernel, the following vulnerability has been resolved:

HID: ft260: fix stack-use-after-return write in I2C read race

ft260 i2c read() points dev->read buf at a caller-supplied buffer (often an on-stack variable), arms a completion and waits up to five seconds for the device to return the data. The HID input callback ft260 raw event() runs in the input/IRQ path, independent of the dev->lock mutex held by the read path, and copies the device-supplied payload into dev->read buf after a plain NULL check.

These two paths share read buf, read idx and read len with no serialization. If the device delays its response until the read times out, ft260 i2c read() resets the controller, clears read buf and returns, unwinding the stack frame the buffer lived in. A response that arrives at that moment lets ft260 raw event() pass the NULL check and then memcpy() the device-controlled payload into the now-freed stack location, a bounded but attacker-influenced stack-use-after-return write triggerable by malicious or malfunctioning hardware.

Add a dedicated spinlock that serializes every access to read buf, read idx and read len. ft260 raw event() now holds it across the NULL check, the memcpy and the index update, while the read path takes it when arming and when clearing the buffer, so the teardown can no longer slip between the check and the copy.