{"id":"CVE-2026-98239","summary":"net: lan743x: fix RX checksum use-after-free","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: lan743x: fix RX checksum use-after-free\n\nlan743x_rx_process_buffer() adds each non-first receive buffer to the\nhead skb's frag_list.  On the last descriptor, lan743x_rx_trim_skb()\nlinearizes the head and frees the fragment skb metadata.\n\nThe checksum-success path then writes ip_summed through the local skb\npointer, which still points to the final fragment.  This causes a\nuse-after-free write when a packet spans more than one receive buffer.\n\nSet ip_summed on the surviving head skb instead.  Multi-buffer receive\ncan occur after a live MTU increase because existing ring entries keep\ntheir old buffer size until they are replenished.\n\nA KUnit test invoking lan743x_rx_process_buffer() with a two-buffer\npacket produced a one-byte KASAN use-after-free write before this change.\nThe same test passed after the change.  The driver object also builds\nwith W=1.  This was not tested on physical LAN743x hardware.","modified":"2026-10-09T02:30:45.057088503Z","published":"2026-10-06T08:45:10.611Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98239.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0e52886c4324c9897c2c62f92be3dc8316cee67e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/161a403c8625e152de03d1da22bbf9cda6dc9f9f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5c216bfa9fb7b36804485e67975e9c98055b31ef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6fe5c3a2503983abb431d93faeadfc7f5e6a7e33"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a58024835c704419bb46d2a34e5223f65605f958"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a9ce4053dc945c5372dedba5017ee675b30dc0c5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98239.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98239"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a"},{"fixed":"0e52886c4324c9897c2c62f92be3dc8316cee67e"},{"fixed":"a58024835c704419bb46d2a34e5223f65605f958"},{"fixed":"6fe5c3a2503983abb431d93faeadfc7f5e6a7e33"},{"fixed":"5c216bfa9fb7b36804485e67975e9c98055b31ef"},{"fixed":"161a403c8625e152de03d1da22bbf9cda6dc9f9f"},{"fixed":"a9ce4053dc945c5372dedba5017ee675b30dc0c5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98239.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"6.1.189"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.54"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98239.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}