CVE-2026-68293

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

net/mlx5: Fix MCIA register buffer overflow on 32 dword reads

The MCIA register can return up to 32 dwords (128 bytes) when the device advertises the mcia32dwords capability, but struct mlx5ifcmciaregbits only defines dword0..11, leaving room for just 12 dwords (48 bytes) of data.

mlx5querymcia() clamps the read size to mlx5mciamaxbytes() and then memcpy()s that many bytes out of the register, potentially reading past the end of the 'out' buffer. On kernels built with FORTIFYSOURCE this is caught as a buffer overflow while reading the module EEPROM via ethtool:

detected buffer overflow in memcpy kernel BUG at lib/stringhelpers.c:1048! RIP: 0010:fortifypanic+0x13/0x20 Call Trace: mlx5querymcia.isra.0+0x200/0x210 [mlx5core] mlx5querymoduleeeprombypage+0x4a/0xa0 [mlx5core] mlx5egetmoduleeeprombypage+0xbb/0x120 [mlx5core] eeprompreparedata+0xf3/0x170 ethnldefault_doit+0xf1/0x3b0

Extend the mcia_reg layout to 32 dwords.