CVE-2026-23231

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: fix use-after-free in nf_tables_addchain() nf_tables_addchain() publishes the chain to table->chains via list_add_tail_rcu() (in nft_chain_add()) before registering hooks. If nf_tables_register_hook() then fails, the error path calls nft_chain_del() (list_del_rcu()) followed by nf_tables_chain_destroy() with no RCU grace period in between. This creates two use-after-free conditions: 1) Control-plane: nf_tables_dump_chains() traverses table->chains under rcu_read_lock(). A concurrent dump can still be walking the chain when the error path frees it. 2) Packet path: for NFPROTO_INET, nf_register_net_hook() briefly installs the IPv4 hook before IPv6 registration fails. Packets entering nft_do_chain() via the transient IPv4 hook can still be dereferencing chain->blob_gen_X when the error path frees the chain. Add synchronize_rcu() between nft_chain_del() and the chain destroy so that all RCU readers -- both dump threads and in-flight packet evaluation -- have finished before the chain is freed.

PUBLISHED Reserved 2026-01-13 | Published 2026-03-04 | Updated 2026-03-04 | Assigner Linux

Product status

References

git.kernel.org/...c/2a6586ecfa4ce1413daaafee250d2590e05f1a33

git.kernel.org/...c/7017745068a9068904e1e7a1b170a5785647cc81

git.kernel.org/...c/f3fe58ce37926a10115ede527d59b91bcc05400a

git.kernel.org/...c/dbd0af8083dd201f07c49110b2ee93710abdff28

git.kernel.org/...c/2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b

git.kernel.org/...c/71e99ee20fc3f662555118cf1159443250647533

cve.org (CVE-2026-23231)

nvd.nist.gov (CVE-2026-23231)

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