{"id":"CVE-2026-31665","revision":"c16270563b2641ed9b8cc23f066aba46","records":[{"revision":"c16270563b2641ed9b8cc23f066aba46","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-31665","aliases":[],"title":"netfilter: nft_ct: fix use-after-free in timeout object destroy","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: fix use-after-free in timeout object destroy\n\nnft_ct_timeout_obj_destroy() frees the timeout object with kfree()\nimmediately after nf_ct_untimeout(), without waiting for an RCU grace\nperiod. Concurrent packet processing on other CPUs may still hold\nRCU-protected references to the timeout object obtained via\nrcu_dereference() in nf_ct_timeout_data().\n\nAdd an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer\nfreeing until after an RCU grace period, matching the approach already\nused in nfnetlink_cttimeout.c.\n\nKASAN report:\n BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0\n Read of size 4 at addr ffff8881035fe19c by task exploit/80\n\n Call Trace:\n  nf_conntrack_tcp_packet+0x1381/0x29d0\n  nf_conntrack_in+0x612/0x8b0\n  nf_hook_slow+0x70/0x100\n  __ip_local_out+0x1b2/0x210\n  tcp_sendmsg_locked+0x722/0x1580\n  __sys_sendto+0x2d8/0x320\n\n Allocated by task 75:\n  nft_ct_timeout_obj_init+0xf6/0x290\n  nft_obj_init+0x107/0x1b0\n  nf_tables_newobj+0x680/0x9c0\n  nfnetlink_rcv_batch+0xc29/0xe00\n\n Freed by task 26:\n  nft_obj_destroy+0x3f/0xa0\n  nf_tables_trans_destroy_work+0x51c/0x5c0\n  process_one_work+0x2c4/0x5a0","state":0,"publishedAt":"2026-04-24T14:45:14.613+00:00","modifiedAt":"2026-10-19T18:56:02.639+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/netfilter/nf_conntrack_timeout.h\",\n                        \"net/netfilter/nft_ct.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"c458fc1c278a65ad5381083121d39a479973ebed\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"c581e5c8f2b59158f62efe61c1a3dc36189081ff\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"f16fe84879a5280f05ebbcea593a189ba0f3e79a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"070abdf1b04325b21a20a2a0c39a2208af107275\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"b42aca3660dc2627a29a38131597ca610dc451f9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"d0983b48c10d1509fd795c155f8b1e832e1369ff\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e0b2b57f01d183e1c84114f1f2287737358d748\",\n                            \"lessThan\": \"f8dca15a1b190787bbd03285304b569631160eda\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/netfilter/nf_conntrack_timeout.h\",\n                        \"net/netfilter/nft_ct.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.19\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.253\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.203\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.169\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.135\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.82\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.23\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.19.13\",\n                            \"lessThanOrEqual\": \"6.19.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/c458fc1c278a65ad5381083121d39a479973ebed","https://git.kernel.org/stable/c/c581e5c8f2b59158f62efe61c1a3dc36189081ff","https://git.kernel.org/stable/c/f16fe84879a5280f05ebbcea593a189ba0f3e79a","https://git.kernel.org/stable/c/070abdf1b04325b21a20a2a0c39a2208af107275","https://git.kernel.org/stable/c/aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77","https://git.kernel.org/stable/c/b42aca3660dc2627a29a38131597ca610dc451f9","https://git.kernel.org/stable/c/d0983b48c10d1509fd795c155f8b1e832e1369ff","https://git.kernel.org/stable/c/f8dca15a1b190787bbd03285304b569631160eda"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31665","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-31665","identifiers":["CVE-2026-31665"]},"retained":false,"historicalAffected":[]}],"coverage":[]}