CVE-2026-98239: Linux

High severity, CVSS 8.1. EPSS: 0.5% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net: lan743x: fix RX checksum use-after-free lan743x_rx_process_buffer() adds each non-first receive buffer to the head skb's frag_list. On the last descriptor, lan743x_rx_trim_skb() linearizes the head and frees the fragment skb metadata. The checksum-success path then writes ip_summed through the local skb pointer, which still points to the final fragment. This causes a use-after-free write when a packet spans more than one receive buffer. Set ip_summed on the surviving head skb instead. Multi-buffer receive can occur after a live MTU increase because existing ring entries keep their old buffer size until they are replenished. A KUnit test invoking lan743x_rx_process_buffer() with a two-buffer packet produced a one-byte KASAN use-after-free write before this change. The same test passed after the change. The driver object also builds with W=1. This was not tested on physical LAN743x hardware.

Affected products

• Linux Linux: from 6.1, before 6.1.189 (fixed in 6.1.189); from 6.2, before 6.6.158 (fixed in 6.6.158); from 6.7, before 6.12.112 (fixed in 6.12.112); from 6.13, before 6.18.54 (fixed in 6.18.54); from 6.19, before 7.2.8 (fixed in 7.2.8)

Published 2026-10-06. Last modified 2026-10-07.