{"id":"CVE-2026-23231","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: fix use-after-free in nf_tables_addchain()\n\nnf_tables_addchain() publishes the chain to table->chains via\nlist_add_tail_rcu() (in nft_chain_add())…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: fix use-after-free in nf_tables_addchain()\n\nnf_tables_addchain() publishes the chain to table->chains via\nlist_add_tail_rcu() (in nft_chain_add())…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 3.16, < 6.1.165","linux_kernel >= 6.2, < 6.6.128","linux_kernel >= 6.7, < 6.12.75","linux_kernel >= 6.13, < 6.18.14","linux_kernel >= 6.19, < 6.19.4"],"patched":["linux_kernel 6.19.4"],"published":"2026-03-04","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:43.953","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-23231","references":[{"url":"https://git.kernel.org/stable/c/2a6586ecfa4ce1413daaafee250d2590e05f1a33","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7017745068a9068904e1e7a1b170a5785647cc81","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/71e99ee20fc3f662555118cf1159443250647533","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dbd0af8083dd201f07c49110b2ee93710abdff28","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f3fe58ce37926a10115ede527d59b91bcc05400a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-253495.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","exploit-available","cve.org"],"epss":0.0103,"epssPercentile":0.63549,"exploits":{"exploitdb":true,"checkedAt":"2026-10-27T17:02:44.815Z"},"exploitAvailable":true,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-06-16T20:18:23.569815Z"},"ingestedAt":"2026-09-08T15:33:26.993Z","slug":"CVE-2026-23231","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: fix use-after-free in nf_tables_addchain()\n\nnf_tables_addchain() publishes the chain to table->chains via\nlist_add_tail_rcu() (in nft_chain_add()) before registering hooks.\nIf nf_tables_register_hook() then fails, the error path calls\nnft_chain_del() (list_del_rcu()) followed by nf_tables_chain_destroy()\nwith no RCU grace period in between.\n\nThis creates two use-after-free conditions:\n\n 1) Control-plane: nf_tables_dump_chains() traverses table->chains\n    under rcu_read_lock(). A concurrent dump can still be walking\n    the chain when the error path frees it.\n\n 2) Packet path: for NFPROTO_INET, nf_register_net_hook() briefly\n    installs the IPv4 hook before IPv6 registration fails.  Packets\n    entering nft_do_chain() via the transient IPv4 hook can still be\n    dereferencing chain->blob_gen_X when the error path frees the\n    chain.\n\nAdd synchronize_rcu() between nft_chain_del() and the chain destroy\nso that all RCU readers -- both dump threads and in-flight packet\nevaluation -- have finished before the chain is freed.\n\n## Affected\n\n- `linux_kernel >= 3.16, < 6.1.165`\n- `linux_kernel >= 6.2, < 6.6.128`\n- `linux_kernel >= 6.7, < 6.12.75`\n- `linux_kernel >= 6.13, < 6.18.14`\n- `linux_kernel >= 6.19, < 6.19.4`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.19.4`","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0.2,"exploitation":12,"ransomware":0},"changes":[]}