CVE-2026-98239

NameCVE-2026-98239
DescriptionIn 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4841-1, DLA-4850-1, DSA-6568-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bookworm6.1.176-1vulnerable
bookworm (security)6.1.190-1fixed
trixie6.12.107-1vulnerable
trixie (security)6.12.113-1fixed
forky, sid7.2.12-1fixed
linux-6.12 (PTS)bookworm (security)6.12.113-1~deb12u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebookworm6.1.190-1DLA-4841-1
linuxsourcetrixie6.12.113-1DSA-6568-1
linuxsource(unstable)7.2.8-1
linux-6.12sourcebookworm6.12.113-1~deb12u1DLA-4850-1

Notes

https://git.kernel.org/linus/a9ce4053dc945c5372dedba5017ee675b30dc0c5 (7.3-rc4)

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