{"id":"CVE-2024-50256","summary":"netfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6()\n\nI got a syzbot report without a repro [1] crashing in nf_send_reset6()\n\nI think the issue is that dev-\u003ehard_header_len is zero, and we attempt\nlater to push an Ethernet header.\n\nUse LL_MAX_HEADER, as other functions in net/ipv6/netfilter/nf_reject_ipv6.c.\n\n[1]\n\nskbuff: skb_under_panic: text:ffffffff89b1d008 len:74 put:14 head:ffff88803123aa00 data:ffff88803123a9f2 tail:0x3c end:0x140 dev:syz_tun\n kernel BUG at net/core/skbuff.c:206 !\nOops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 0 UID: 0 PID: 7373 Comm: syz.1.568 Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\n RIP: 0010:skb_panic net/core/skbuff.c:206 [inline]\n RIP: 0010:skb_under_panic+0x14b/0x150 net/core/skbuff.c:216\nCode: 0d 8d 48 c7 c6 60 a6 29 8e 48 8b 54 24 08 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 41 54 41 57 41 56 e8 ba 30 38 02 48 83 c4 20 90 \u003c0f\u003e 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3\nRSP: 0018:ffffc900045269b0 EFLAGS: 00010282\nRAX: 0000000000000088 RBX: dffffc0000000000 RCX: cd66dacdc5d8e800\nRDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000000\nRBP: ffff88802d39a3d0 R08: ffffffff8174afec R09: 1ffff920008a4ccc\nR10: dffffc0000000000 R11: fffff520008a4ccd R12: 0000000000000140\nR13: ffff88803123aa00 R14: ffff88803123a9f2 R15: 000000000000003c\nFS:  00007fdbee5ff6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000000 CR3: 000000005d322000 CR4: 00000000003526f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \u003cTASK\u003e\n  skb_push+0xe5/0x100 net/core/skbuff.c:2636\n  eth_header+0x38/0x1f0 net/ethernet/eth.c:83\n  dev_hard_header include/linux/netdevice.h:3208 [inline]\n  nf_send_reset6+0xce6/0x1270 net/ipv6/netfilter/nf_reject_ipv6.c:358\n  nft_reject_inet_eval+0x3b9/0x690 net/netfilter/nft_reject_inet.c:48\n  expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]\n  nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288\n  nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161\n  nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]\n  nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626\n  nf_hook include/linux/netfilter.h:269 [inline]\n  NF_HOOK include/linux/netfilter.h:312 [inline]\n  br_nf_pre_routing_ipv6+0x63e/0x770 net/bridge/br_netfilter_ipv6.c:184\n  nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]\n  nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]\n  br_handle_frame+0x9fd/0x1530 net/bridge/br_input.c:424\n  __netif_receive_skb_core+0x13e8/0x4570 net/core/dev.c:5562\n  __netif_receive_skb_one_core net/core/dev.c:5666 [inline]\n  __netif_receive_skb+0x12f/0x650 net/core/dev.c:5781\n  netif_receive_skb_internal net/core/dev.c:5867 [inline]\n  netif_receive_skb+0x1e8/0x890 net/core/dev.c:5926\n  tun_rx_batched+0x1b7/0x8f0 drivers/net/tun.c:1550\n  tun_get_user+0x3056/0x47e0 drivers/net/tun.c:2007\n  tun_chr_write_iter+0x10d/0x1f0 drivers/net/tun.c:2053\n  new_sync_write fs/read_write.c:590 [inline]\n  vfs_write+0xa6d/0xc90 fs/read_write.c:683\n  ksys_write+0x183/0x2b0 fs/read_write.c:736\n  do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fdbeeb7d1ff\nCode: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 c9 8d 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 1c 8e 02 00 48\nRSP: 002b:00007fdbee5ff000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001\nRAX: ffffffffffffffda RBX: 00007fdbeed36058 RCX: 00007fdbeeb7d1ff\nRDX: 000000000000008e RSI: 0000000020000040 RDI: 00000000000000c8\nRBP: 00007fdbeebf12be R08: 0000000\n---truncated---","modified":"2026-04-16T04:32:16.467024294Z","published":"2024-11-09T10:15:09.551Z","related":["ALSA-2024:10943","ALSA-2024:10944","SUSE-SU-2025:0117-1","SUSE-SU-2025:0153-1","SUSE-SU-2025:0154-1","SUSE-SU-2025:0201-1","SUSE-SU-2025:0201-2","SUSE-SU-2025:0229-1","SUSE-SU-2025:0236-1","SUSE-SU-2025:0289-1","SUSE-SU-2025:20165-1","SUSE-SU-2025:20166-1","SUSE-SU-2025:20248-1","SUSE-SU-2025:20249-1","USN-7276-1","USN-7277-1","openSUSE-SU-2024:14500-1","openSUSE-SU-2025:14705-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50256.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4ed234fe793f27a3b151c43d2106df2ff0d81aac"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4f7b586aae53c2ed820661803da8ce18b1361921"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f85b057e34419e5ec0583a65078a11ccc1d4540a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fef63832317d9d24e1214cdd8f204d02ebdf8499"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50256.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-50256"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c8d7b98bec43faaa6583c3135030be5eb4693acb"},{"fixed":"4f7b586aae53c2ed820661803da8ce18b1361921"},{"fixed":"fef63832317d9d24e1214cdd8f204d02ebdf8499"},{"fixed":"f85b057e34419e5ec0583a65078a11ccc1d4540a"},{"fixed":"4ed234fe793f27a3b151c43d2106df2ff0d81aac"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50256.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}