CVE-2026-90059

/// Technical description

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

net: stmmac: restore NET_IP_ALIGN in the RX DMA offset

Since the RX path was converted to zero-copy, the page pool page is handed

to the stack directly as the skb head, and the offset the DMA engine writes

at is what determines the alignment of the packet headers.

Before the conversion the payload was copied into an skb obtained from

napi_alloc_skb(), which reserves NET_SKB_PAD + NET_IP_ALIGN. The

conversion moved the headroom into stmmac_rx_offset() but did not carry

over NET_IP_ALIGN, so on architectures where NET_IP_ALIGN is 2 the IP

header now lands misaligned:

64 (NET_SKB_PAD) + 14 (ethernet) + 20 (IP) = 98

Same for the XDP branch:

256 (XDP_PACKET_HEADROOM) + 14 (ethernet) + 20 (IP) = 290

On ARM32 this is fatal, because ldm and ldrd trap on unaligned addresses

even when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set.

Any received echo request panics the machine, e.g:

Unhandled fault: alignment except

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References