CVE Catalog

CVE-2026-98239

HighCVSS 8.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.47%

40th percentile - higher than 40% of all known CVEs

Summary

In the Linux kernel lan743x driver, lan743x_rx_process_buffer() adds each non-first receive buffer to the head skb's frag_list, and lan743x_rx_trim_skb() then linearizes the head and frees the fragment skb metadata. The checksum-success path still writes ip_summed through the local skb pointer that points to the freed fragment, causing a use-after-free write when a packet spans more than one receive buffer.

Risk Assessment

This can cause kernel memory corruption (use-after-free write) and potentially privilege escalation or system crash when multi-buffer packets are received, e.g. after a live MTU increase on the interface.

Recommendation

Update the Linux kernel to a version containing the fix that sets ip_summed on the surviving head skb instead of the freed fragment.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS