{"id":11247,"date":"2026-09-04T18:53:06","date_gmt":"2026-09-04T10:53:06","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-74660"},"modified":"2026-09-04T18:53:06","modified_gmt":"2026-09-04T10:53:06","slug":"cve-2026-74660","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-74660","title":{"rendered":"CVE-2026-74660 [HIGH] &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebt_nflog:"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>netfilter: ebt_nflog: pin the NFLOG backend<\/p>\n<p>nf_log_unregister() runs after the per-net teardown so its final RCU<br \/>\ngrace period also drains readers that obtained the logger from a per-net<br \/>\nbinding.  However, ebt_nflog passes an explicit ULOG log type to<br \/>\nnf_log_packet() without holding a reference on the selected logger module,<br \/>\nunlike the xt_NFLOG and nft_log frontends.<\/p>\n<p>An ebtables nflog rule can therefore remain callable while nfnetlink_log<br \/>\nis unloaded.  The resulting interleaving is:<\/p>\n<p>  CPU 0                               CPU 1<br \/>\n  nfnetlink_log_fini()<br \/>\n    unregister_pernet_subsys()<br \/>\n      kfree(nfnl_log_pernet(net))<br \/>\n                                      ebt_nflog_tg()<br \/>\n                                        nf_log_packet()<br \/>\n                                          nfulnl_log_packet()<br \/>\n                                            instance_lookup_get_rcu()<\/p>\n<p>The global ULOG logger is still registered at this point, so CPU 1<br \/>\ndereferences the per-net state after CPU 0 has freed it.  KASAN reported:<\/p>\n<p>  BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu<br \/>\n  Read of size 8 at addr ff110001052e6210 by task poc\/92<br \/>\n  Call Trace:<br \/>\n   instance_lookup_get_rcu+0x1ce\/0x1f0 [nfnetlink_log]<br \/>\n   nfulnl_log_packet+0x248\/0x2fb0 [nfnetlink_log]<br \/>\n   nf_log_packet+0x204\/0x300<br \/>\n   ebt_nflog_tg+0x351\/0x550<br \/>\n   ebt_do_table+0xedf\/0x22b0<br \/>\n  Allocated by task 90:<br \/>\n   __kmalloc_noprof+0x186\/0x470<br \/>\n   ops_init+0x6d\/0x420<br \/>\n   register_pernet_operations+0x2f6\/0x670<br \/>\n   register_pernet_subsys+0x23\/0x40<br \/>\n  Freed by task 93:<br \/>\n   kfree+0x131\/0x3c0<br \/>\n   ops_undo_list+0x3e3\/0x700<br \/>\n   unregister_pernet_operations+0x232\/0x490<br \/>\n   unregister_pernet_subsys+0x1c\/0x30<br \/>\n   nfnetlink_log_fini+0x34\/0x450 [nfnetlink_log]<\/p>\n<p>Acquire the ULOG logger module reference when an ebt_nflog rule is<br \/>\nvalidated and release it when the rule is destroyed.  Request the NFLOG<br \/>\nbackend for legacy callers when needed, matching xt_NFLOG.  This prevents<br \/>\nmodule teardown until all ebt_nflog rules have stopped using the logger.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>netfilter: ebt_nflog: pin the NFLOG backend<\/p>\n<p>nf_log_unregister() runs after the per-net teardown so its final RCU<br \/>\ngrace period also<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-11247","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/11247","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11247"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11247"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11247"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}