CVE-2026-89628
2026-09-11
20h19 +00:00
20h19 +00:00
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Mô tả CVE
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.
