CVE-2026-90059

Status: UPDATED  |  Advisory ID: CVE-2026-90059

Key Details

Affected Products, Subsystems & Sectors

What to Know

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 exception (0x001) at 0x81873062

Internal error: : 1 [#1] SMP ARM

Hardware name: Altera SOCFPGA Arria10

PC is at icmp_echo+0x38/0xa8

LR is at icmp_rcv+0x22c/0x370

Call trace:

icmp_echo from icmp_rcv+0x22c/0x370

icmp_rcv from ip_protocol_deliver_rcu+0x2c/0x224

ip_protocol_deliver_rcu from ip_local_deliver+0xc8/0x1a0

ip_local_deliver from ip_sublist_rcv_finish+0x3c/0x50

ip_sublist_rcv_finish from ip_list_rcv_finish+0x110/0x118

ip_list_rcv_finish from ip_list_rcv+0xc8/0xdc

ip_list_rcv from __netif_receive_skb_list_core+0x170/0x1c0

...

napi_complete_done from stmmac_napi_poll_rx+0xcb0/0x1030

Code: e24dd068 e59020a0 e28dc010 e0822001 (e8920003)

Kernel panic - not syncing: Fatal exception in interrupt

The faulting instruction is the ldm of *icmp_hdr(skb) in icmp_echo().

Fix by adding NET_IP_ALIGN back to the RX offset, which restores the

alignment the stack used to get.

Note that commit a955318fe67e ("stmmac: align RX buffers") made a similar

change in 2021 and was reverted by commit 12d125b4574b ("stmmac: Revert

"stmmac: align RX buffers"") because it caused packet corruption. That

patch raised the offset from 0 without adjusting the buffer size

accounting, so the DMA engine could arguably write past the end of the RX

buffers, though this was never root caused.

Commit df542f669307 ("net: stmmac: Switch to zero-copy in non-XDP RX

path") since derives the page pool allocation from stmmac_rx_offset(), so

the extra bytes are accounted for. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References