CVE-2026-89628

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

HID: picolcd: clamp eeprom debugfs read to bytes actually received

picolcd_debug_eeprom_read() trusts resp->raw_data[2] -- a length byte

supplied by the device in its REPORT_EE_DATA reply -- clamped only to

the caller's read() count:

ret = resp->raw_data[2];

if (ret > s)

ret = s;

if (copy_to_user(u, resp->raw_data+3, ret))

It never checks resp->raw_size, the number of bytes picolcd_raw_event()

actually copied into the 64-byte raw_data[] of the kmalloc'd struct

picolcd_pending. A device (or a spoofed picoLCD) returning a length byte

of 0xff, read with a count >= 255, makes copy_to_user() read past

raw_data[] into adjacent slab memory and return it to userspace through

the debugfs "eeprom" file:

BUG: KASAN: slab-out-of-bounds in _copy_to_user

Read of size 255 ... picolcd_debug_eeprom_read+0x214/0x2f0 [hid_picolcd]

The debug-dump path in the same file already validates the device length

byte against the received size before trusting it; this read does not.

The file is created S_IRUSR (root-only) and a crafted device is needed,

so it is neither unprivileged- nor remotely-triggerable.

Clamp the copy length to resp->raw_size - 3 (the payload actually

received, minus the 3-byte header), floored at 0 for short replies.