# CVE-2026-90059: net: stmmac: restore NET_IP_ALIGN in the RX DMA offset

CVE-2026-90059 is fixed in linux on 1 platform by DEBIAN-CVE-2026-90059 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-90059
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0061
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-90059

## 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 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-90059](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90059.md) | Sep 23, 2026 |

---

Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.