UBUNTU-CVE-2026-23231
Vulnerability Summary
Timeline
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.
CVSS Metrics
- v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Systems
- ubuntu•linux
all | all | all | all | < 6.8.0-111.111 | < 6.17.0-23.23
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
all | all | all | all | < 6.8.0-1053.56 | < 6.17.0-1013.13
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.15
all
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.4
all
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.14
all
- ubuntu•linux-aws-6.17
all | < 6.17.0-1013.13~24.04.1
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-aws-6.8
all | < 6.8.0-1053.56~22.04.1
- ubuntu•linux-aws-fips
all | < 6.8.0-1053.56+fips1
- ubuntu•linux-aws-hwe
all
- ubuntu•linux-azure
all | all | all | all | all | < 6.8.0-1054.60 | < 6.17.0-1013.13
- ubuntu•linux-azure-4.15
all
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.15
all
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.4
all
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.11
all
- ubuntu•linux-azure-6.14
all
- ubuntu•linux-azure-6.17
all | < 6.17.0-1013.13~24.04.1
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-6.8
all
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | all | all | all
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.14
all
- ubuntu•linux-azure-fde-6.17
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fde-6.8
all
- ubuntu•linux-azure-fips
all | < 6.8.0-1054.60+fips1
- ubuntu•linux-azure-nvidia
all
- ubuntu•linux-azure-nvidia-6.14
all
- ubuntu•linux-bluefield
all | all
- ubuntu•linux-fips
all | < 6.8.0-111.111+fips1
- ubuntu•linux-gcp
all | all | all | all | all | < 6.8.0-1055.58 | < 6.17.0-1013.13
- ubuntu•linux-gcp-4.15
all
- ubuntu•linux-gcp-5.11
all
- ubuntu•linux-gcp-5.13
all
- ubuntu•linux-gcp-5.15
all
Showing first 50 affected entries in server-rendered view.
References (18)
- https://ubuntu.com/security/CVE-2026-23231
- https://www.cve.org/CVERecord?id=CVE-2026-23231
- https://git.kernel.org/linus/71e99ee20fc3f662555118cf1159443250647533
- https://git.kernel.org/stable/c/2a6586ecfa4ce1413daaafee250d2590e05f1a33
- https://git.kernel.org/stable/c/2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b
- https://git.kernel.org/stable/c/7017745068a9068904e1e7a1b170a5785647cc81
- https://git.kernel.org/stable/c/71e99ee20fc3f662555118cf1159443250647533
- https://git.kernel.org/stable/c/dbd0af8083dd201f07c49110b2ee93710abdff28
- https://git.kernel.org/stable/c/f3fe58ce37926a10115ede527d59b91bcc05400a
- https://ubuntu.com/security/notices/USN-8244-1
- https://ubuntu.com/security/notices/USN-8245-1
- https://ubuntu.com/security/notices/USN-8254-1
- https://ubuntu.com/security/notices/USN-8257-1
- https://ubuntu.com/security/notices/USN-8258-1
- https://ubuntu.com/security/notices/USN-8260-1
- https://ubuntu.com/security/notices/USN-8261-1
- https://ubuntu.com/security/notices/USN-8254-2
- https://ubuntu.com/security/notices/USN-8254-3