CVE-2026-80664

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_nat: reject unsupported target families xt_nat SNAT and DNAT target handlers assume IP-family conntrack state is present and can dereference a NULL pointer when instantiated from an unsupported family through nft_compat. A bridge-family compat rule can therefore trigger a NULL-dereference in nf_nat_setup_info(). Reject non-IP families in xt_nat_checkentry() so unsupported targets cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT compat users and leave the runtime fast path unchanged. [ The crash was fixed via 9dbba7e694ec ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"), so this patch is no longer critical. Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra family check is a good idea in any case. ]

References

• https://git.kernel.org/stable/c/0afc9ad987c0faa80ab5f8d6e7815085ac8dbb82
• https://git.kernel.org/stable/c/49abe564391411057a26a9a943c8e17867c3b9b4
• https://git.kernel.org/stable/c/4fbc2bac02edabb665beb2aa87ca6f1e1d4c4777
• https://git.kernel.org/stable/c/5d1a2240935ea47e2673d0ea17fdb058e4dc91dd
• https://git.kernel.org/stable/c/679ced28a9dc2f6dc679eb05027d779693e60902