{ "affected": [ { "ranges": [ { "events": [ { "introduced": "67cc570edaa02016a8685a06a0ee91f05a6277d9" }, { "fixed": "df86c0e84025be8b6dd572a20852698927aa666b" }, { "fixed": "6fa88d11983c6fe693c13ed7c5b3b75ae9f39de6" }, { "fixed": "e97e2d6d0b150fd78be573f9fdf193f204d9334e" }, { "fixed": "68de7f3a38acab355c24114f77bf00d3094ce4da" }, { "fixed": "7904b94768e983bcb2be34a8d6d1f3450f5b838b" } ], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "type": "GIT" } ] }, { "package": { "ecosystem": "Linux", "name": "Kernel" }, "ranges": [ { "events": [ { "introduced": "5.9.0" }, { "fixed": "6.12.108" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.13.0" }, { "fixed": "6.18.49" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.19.0" }, { "fixed": "7.1.13" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "7.2.0" }, { "fixed": "7.2.3" } ], "type": "ECOSYSTEM" } ] } ], "database_specific": { "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80837.json" }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: don't queue packet path object notifications\n\nAll file:line references below are against v7.2-rc4 (ac5b0e5651b1). The\ntrace was captured on 7.2.0-rc6-kasan72rc6 (075b74841bd0), where the same\nlines apply.\n\nnft_obj_notify() is exported and reached from the packet path. Its only\nin-tree caller is nft_quota_obj_eval() (net/netfilter/nft_quota.c:68),\nwhich notifies with GFP_ATOMIC while evaluating a rule for a transiting\npacket, holding no mutex.\n\nSince commit 67cc570edaa0 (\"netfilter: nf_tables: coalesce multiple\nnotifications into one skbuff\") that notification is no longer sent\nimmediately. __nft_obj_notify() queues it onto nft_net-\u003enotify_list via\nnft_notify_enqueue() (net/netfilter/nf_tables_api.c:1211), which is a bare\nlist_add_tail(). notify_list has no lock of its own\n(include/net/netfilter/nf_tables.h:1951), it is serialised by commit_mutex:\nthe six other enqueue sites all run inside a netlink transaction, and the\ndrain in nft_commit_notify() (net/netfilter/nf_tables_api.c:10746) does\nlist_del() + kfree_skb() from nf_tables_commit() with commit_mutex held.\n\nSending packets through a chain that references a depleted quota object\ntherefore races an unlocked list_add_tail() against list_del() +\nkfree_skb() on another CPU. The WRITE_ONCE(prev-\u003enext, new) in __list_add()\nthen stores through an sk_buff that has already been freed:\n\n BUG: KASAN: slab-use-after-free in __nft_obj_notify+0x2c5/0x2d0\n Write of size 8 at addr ff110001047183c0 by task poc/76\n CPU: 0 UID: 1000 PID: 76 Comm: poc Tainted: G W 7.2.0-rc6-kasan72rc6 #4\n Call Trace:\n \u003cIRQ\u003e\n __nft_obj_notify (include/linux/list.h:164 include/linux/list.h:191\n net/netfilter/nf_tables_api.c:1211\n net/netfilter/nf_tables_api.c:8743)\n nft_quota_obj_eval (net/netfilter/nft_quota.c:68)\n nft_do_chain_inet\n nf_hook_slow\n __ip_local_out\n ip_push_pending_frames\n udp_send_skb\n udp_sendmsg\n __x64_sys_sendto\n\n Allocated by task 77:\n __alloc_skb (net/core/skbuff.c:704)\n __nft_obj_notify (include/net/netlink.h:1055\n net/netfilter/nf_tables_api.c:8731)\n nft_quota_obj_eval (net/netfilter/nft_quota.c:68)\n nft_do_chain\n\n Freed by task 79:\n nf_tables_commit (include/linux/skbuff.h:1332\n net/netfilter/nf_tables_api.c:10759\n net/netfilter/nf_tables_api.c:11185)\n nfnetlink_rcv_batch (net/netfilter/nfnetlink.c:574)\n netlink_unicast\n netlink_sendmsg\n\n The buggy address belongs to the cache skbuff_head_cache of size 232\n\nQueueing from the packet path is wrong even leaving the race aside:\nnotify_list is only drained by nft_commit_notify() from nf_tables_commit()\n(:11185), so a notification enqueued outside a transaction is not sent\nuntil some later netlink batch commits, if one ever does.\n\nThe gfp argument that nft_obj_notify() still takes is a leftover of the\npre-67cc570edaa0 behaviour, where this path called nfnetlink_send()\ndirectly. Restore that: split the message construction out into\nnft_obj_notify_alloc() and let each caller decide what to do with the skb.\nnft_obj_notify(), the exported one reached from the packet path, sends it\nstraight away; nf_tables_obj_notify(), which runs under commit_mutex, keeps\nqueueing it, so transaction notifications are still coalesced.", "id": "CVE-2026-80837", "modified": "2026-09-06T03:31:05.071841899Z", "published": "2026-09-04T15:54:47.179Z", "references": [ { "type": "WEB", "url": "https://git.kernel.org/stable/c/68de7f3a38acab355c24114f77bf00d3094ce4da" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/6fa88d11983c6fe693c13ed7c5b3b75ae9f39de6" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/7904b94768e983bcb2be34a8d6d1f3450f5b838b" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/df86c0e84025be8b6dd572a20852698927aa666b" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/e97e2d6d0b150fd78be573f9fdf193f204d9334e" }, { "type": "ADVISORY", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80837.json" }, { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80837" }, { "type": "PACKAGE", "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git" } ], "schema_version": "1.9.0", "summary": "netfilter: nf_tables: don't queue packet path object notifications" }