{"id":"CVE-2026-74660","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebt_nflog: pin the NFLOG backend\n\nnf_log_unregister() runs after the per-net teardown so its final RCU\ngrace period also drains readers that obtained the log…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebt_nflog: pin the NFLOG backend\n\nnf_log_unregister() runs after the per-net teardown so its final RCU\ngrace period also drains readers that obtained the log…","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","published":"2026-08-22","updated":"2026-10-14","sourceUpdated":"2026-10-14T13:10:00.187","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74660","references":[{"url":"https://git.kernel.org/stable/c/2cac4294f184c9bc19ff82552c62b80498694c39","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/30825970339c107bacaf7f61af90fcdb1f597ca1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/394d7939c6b2b9e6bea0844c89efb5913168d898","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3bcce49d617c593c7606083bfdb464a1761fa68d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/47a119ec8a7e2d5c8c4e86fb1a56c4e696e500fb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6809379a860b9fccbb5435bf08343f6d081ac68d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9d8a94b48b393885e7f876c8ef68ed4da5012078","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e2ab7e878bdbe80104c879c31fd2d82a476703b8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00126,"epssPercentile":0.02014,"ingestedAt":"2026-10-14T13:30:58.529Z","slug":"CVE-2026-74660","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebt_nflog: pin the NFLOG backend\n\nnf_log_unregister() runs after the per-net teardown so its final RCU\ngrace period also drains readers that obtained the logger from a per-net\nbinding.  However, ebt_nflog passes an explicit ULOG log type to\nnf_log_packet() without holding a reference on the selected logger module,\nunlike the xt_NFLOG and nft_log frontends.\n\nAn ebtables nflog rule can therefore remain callable while nfnetlink_log\nis unloaded.  The resulting interleaving is:\n\n  CPU 0                               CPU 1\n  nfnetlink_log_fini()\n    unregister_pernet_subsys()\n      kfree(nfnl_log_pernet(net))\n                                      ebt_nflog_tg()\n                                        nf_log_packet()\n                                          nfulnl_log_packet()\n                                            instance_lookup_get_rcu()\n\nThe global ULOG logger is still registered at this point, so CPU 1\ndereferences the per-net state after CPU 0 has freed it.  KASAN reported:\n\n  BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu\n  Read of size 8 at addr ff110001052e6210 by task poc/92\n  Call Trace:\n   instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]\n   nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]\n   nf_log_packet+0x204/0x300\n   ebt_nflog_tg+0x351/0x550\n   ebt_do_table+0xedf/0x22b0\n  Allocated by task 90:\n   __kmalloc_noprof+0x186/0x470\n   ops_init+0x6d/0x420\n   register_pernet_operations+0x2f6/0x670\n   register_pernet_subsys+0x23/0x40\n  Freed by task 93:\n   kfree+0x131/0x3c0\n   ops_undo_list+0x3e3/0x700\n   unregister_pernet_operations+0x232/0x490\n   unregister_pernet_subsys+0x1c/0x30\n   nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]\n\nAcquire the ULOG logger module reference when an ebt_nflog rule is\nvalidated and release it when the rule is destroyed.  Request the NFLOG\nbackend for legacy callers when needed, matching xt_NFLOG.  This prevents\nmodule teardown until all ebt_nflog rules have stopped using the logger.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}