CVE-2026-74737

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

net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG

On the packet reception path, the ID of the MAC Port on which the packet

was received, is embedded in the RX DMA Descriptor's metadata. The ID is

extracted using the helper function cppi5descgettagsids() which fills

in the 16-bit Source Tag into the 'port_id' variable. However, it is only

the lower 8-bits of the 16-bit Source Tag that represent the MAC Port ID,

while the upper 8-bits are Hardware-Reserved and carry an arbitrary value.

With the existing logic, sporadic kernel crash is observed due to the

subsequent driver code accessing out-of-bound memory because of an invalid

port_id.

Hence, fix the port_id extraction logic to use only the lower 8-bits of the

Source Tag as the MAC Port ID.