{"id":"CVE-2026-23458","revision":"f6062419bbe14785abda0f4419b76a20","records":[{"revision":"f6062419bbe14785abda0f4419b76a20","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-23458","aliases":[],"title":"netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()\n\nctnetlink_dump_exp_ct() stores a conntrack pointer in cb->data for the\nnetlink dump callback ctnetlink_exp_ct_dump_table(), but drops the\nconntrack reference immediately after netlink_dump_start(). When the\ndump spans multiple rounds, the second recvmsg() triggers the dump\ncallback which dereferences the now-freed conntrack via nfct_help(ct),\nleading to a use-after-free on ct->ext.\n\nThe bug is that the netlink_dump_control has no .start or .done\ncallbacks to manage the conntrack reference across dump rounds. Other\ndump functions in the same file (e.g. ctnetlink_get_conntrack) properly\nuse .start/.done callbacks for this purpose.\n\nFix this by adding .start and .done callbacks that hold and release the\nconntrack reference for the duration of the dump, and move the\nnfct_help() call after the cb->args[0] early-return check in the dump\ncallback to avoid dereferencing ct->ext unnecessarily.\n\n BUG: KASAN: slab-use-after-free in ctnetlink_exp_ct_dump_table+0x4f/0x2e0\n Read of size 8 at addr ffff88810597ebf0 by task ctnetlink_poc/133\n\n CPU: 1 UID: 0 PID: 133 Comm: ctnetlink_poc Not tainted 7.0.0-rc2+ #3 PREEMPTLAZY\n Call Trace:\n \n ctnetlink_exp_ct_dump_table+0x4f/0x2e0\n netlink_dump+0x333/0x880\n netlink_recvmsg+0x3e2/0x4b0\n ? aa_sk_perm+0x184/0x450\n sock_recvmsg+0xde/0xf0\n\n Allocated by task 133:\n kmem_cache_alloc_noprof+0x134/0x440\n __nf_conntrack_alloc+0xa8/0x2b0\n ctnetlink_create_conntrack+0xa1/0x900\n ctnetlink_new_conntrack+0x3cf/0x7d0\n nfnetlink_rcv_msg+0x48e/0x510\n netlink_rcv_skb+0xc9/0x1f0\n nfnetlink_rcv+0xdb/0x220\n netlink_unicast+0x3ec/0x590\n netlink_sendmsg+0x397/0x690\n __sys_sendmsg+0xf4/0x180\n\n Freed by task 0:\n slab_free_after_rcu_debug+0xad/0x1e0\n rcu_core+0x5c3/0x9c0","state":0,"publishedAt":"2026-04-03T15:15:39.041+00:00","modifiedAt":"2026-10-19T18:35:45.043+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 \"net/netfilter/nf_conntrack_netlink.c\"\n ],\n \"versions\": [\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"d8cd0efbccc5cfb0a80da744a7da76e1333ab925\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"9821b47f669eb82791fa0b1a6ebaf9aa219bea72\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"bdf2724eefd4455a66863abb025bab8d3aa98c57\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"f04cc86d59906513d2d62183b882966fc0ae0390\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"f025171feef2ac65663d7986f1d5ff0c28d6b2a9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"cd541f15b60e2257441398cf495d978f816d09f8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e844a928431fa8f1359d1f4f2cef53d9b446bf52\",\n \"lessThan\": \"5cb81eeda909dbb2def209dd10636b51549a3f8a\",\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 \"net/netfilter/nf_conntrack_netlink.c\"\n ],\n \"versions\": [\n {\n \"version\": \"3.10\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"3.10\",\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\": \"6.1.167\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.130\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.78\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.20\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.19.10\",\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/d8cd0efbccc5cfb0a80da744a7da76e1333ab925","https://git.kernel.org/stable/c/9821b47f669eb82791fa0b1a6ebaf9aa219bea72","https://git.kernel.org/stable/c/bdf2724eefd4455a66863abb025bab8d3aa98c57","https://git.kernel.org/stable/c/f04cc86d59906513d2d62183b882966fc0ae0390","https://git.kernel.org/stable/c/f025171feef2ac65663d7986f1d5ff0c28d6b2a9","https://git.kernel.org/stable/c/04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56","https://git.kernel.org/stable/c/cd541f15b60e2257441398cf495d978f816d09f8","https://git.kernel.org/stable/c/5cb81eeda909dbb2def209dd10636b51549a3f8a"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23458","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-23458","identifiers":["CVE-2026-23458"]},"retained":false,"historicalAffected":[]}],"coverage":[]}