netfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6()
I got a syzbot report without a repro [1] crashing in nf_send_reset6()
I think the issue is that dev->hard_header_len is zero, and we attempt
later to push an Ethernet header.
Use LL_MAX_HEADER, as other functions in net/ipv6/netfilter/nf_reject_ipv6.c.
[1]
skbuff: skb_under_panic: text:ffffffff89b1d008 len:74 put:14 head:ffff88803123aa00 data:ffff88803123a9f2 tail:0x3c end:0x140 dev:syz_tun
kernel BUG at net/core/skbuff.c:206 !
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 UID: 0 PID: 7373 Comm: syz.1.568 Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:skb_panic net/core/skbuff.c:206 [inline]
RIP: 0010:skb_under_panic+0x14b/0x150 net/core/skbuff.c:216
Code: 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 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc900045269b0 EFLAGS: 00010282
RAX: 0000000000000088 RBX: dffffc0000000000 RCX: cd66dacdc5d8e800
RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000000
RBP: ffff88802d39a3d0 R08: ffffffff8174afec R09: 1ffff920008a4ccc
R10: dffffc0000000000 R11: fffff520008a4ccd R12: 0000000000000140
R13: ffff88803123aa00 R14: ffff88803123a9f2 R15: 000000000000003c
FS: 00007fdbee5ff6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005d322000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
skb_push+0xe5/0x100 net/core/skbuff.c:2636
eth_header+0x38/0x1f0 net/ethernet/eth.c:83
dev_hard_header include/linux/netdevice.h:3208 [inline]
nf_send_reset6+0xce6/0x1270 net/ipv6/netfilter/nf_reject_ipv6.c:358
nft_reject_inet_eval+0x3b9/0x690 net/netfilter/nft_reject_inet.c:48
expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288
nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:269 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
br_nf_pre_routing_ipv6+0x63e/0x770 net/bridge/br_netfilter_ipv6.c:184
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
br_handle_frame+0x9fd/0x1530 net/bridge/br_input.c:424
__netif_receive_skb_core+0x13e8/0x4570 net/core/dev.c:5562
__netif_receive_skb_one_core net/core/dev.c:5666 [inline]
__netif_receive_skb+0x12f/0x650 net/core/dev.c:5781
netif_receive_skb_internal net/core/dev.c:5867 [inline]
netif_receive_skb+0x1e8/0x890 net/core/dev.c:5926
tun_rx_batched+0x1b7/0x8f0 drivers/net/tun.c:1550
tun_get_user+0x3056/0x47e0 drivers/net/tun.c:2007
tun_chr_write_iter+0x10d/0x1f0 drivers/net/tun.c:2053
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0xa6d/0xc90 fs/read_write.c:683
ksys_write+0x183/0x2b0 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdbeeb7d1ff
Code: 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 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 1c 8e 02 00 48
RSP: 002b:00007fdbee5ff000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fdbeed36058 RCX: 00007fdbeeb7d1ff
RDX: 000000000000008e RSI: 0000000020000040 RDI: 00000000000000c8
RBP: 00007fdbeebf12be R08: 0000000
---truncated---
Metrics
Affected Vendors & Products
| Source | ID | Title | 
|---|---|---|
  Debian DLA | 
                DLA-4008-1 | linux-6.1 security update | 
  Debian DSA | 
                DSA-5818-1 | linux security update | 
  Ubuntu USN | 
                USN-7276-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7277-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7310-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7449-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7449-2 | Linux kernel (HWE) vulnerabilities | 
  Ubuntu USN | 
                USN-7450-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7451-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7452-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7453-1 | Linux kernel (Real-time) vulnerabilities | 
  Ubuntu USN | 
                USN-7455-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7455-2 | Linux kernel (FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7455-3 | Linux kernel (Real-time) vulnerabilities | 
  Ubuntu USN | 
                USN-7455-4 | Linux kernel (Oracle) vulnerabilities | 
  Ubuntu USN | 
                USN-7455-5 | Linux kernel (AWS) vulnerabilities | 
  Ubuntu USN | 
                USN-7459-1 | Linux kernel (Intel IoTG) vulnerabilities | 
  Ubuntu USN | 
                USN-7459-2 | Linux kernel (GCP) vulnerabilities | 
  Ubuntu USN | 
                USN-7460-1 | Linux kernel (Azure FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7461-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7461-2 | Linux kernel (FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7461-3 | Linux kernel (Xilinx ZynqMP) vulnerabilities | 
  Ubuntu USN | 
                USN-7462-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7462-2 | Linux kernel (AWS FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7463-1 | Linux kernel (IBM) vulnerabilities | 
  Ubuntu USN | 
                USN-7468-1 | Linux kernel (Azure, N-Series) vulnerabilities | 
  Ubuntu USN | 
                USN-7475-1 | Linux kernel (Xilinx ZynqMP) vulnerabilities | 
  Ubuntu USN | 
                USN-7496-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7496-2 | Linux kernel (FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7496-3 | Linux kernel (Azure) vulnerabilities | 
  Ubuntu USN | 
                USN-7496-4 | Linux kernel (Azure) vulnerabilities | 
  Ubuntu USN | 
                USN-7496-5 | Linux kernel (Azure FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7506-1 | Linux kernel vulnerabilities | 
  Ubuntu USN | 
                USN-7506-2 | Linux kernel (AWS) vulnerabilities | 
  Ubuntu USN | 
                USN-7506-3 | Linux kernel (FIPS) vulnerabilities | 
  Ubuntu USN | 
                USN-7506-4 | Linux kernel (Xenial HWE) vulnerabilities | 
  Ubuntu USN | 
                USN-7523-1 | Linux kernel (Raspberry Pi Real-time) vulnerabilities | 
  Ubuntu USN | 
                USN-7524-1 | Linux kernel (Raspberry Pi) vulnerabilities | 
  Ubuntu USN | 
                USN-7539-1 | Linux kernel (Raspberry Pi) vulnerabilities | 
  Ubuntu USN | 
                USN-7540-1 | Linux kernel (Raspberry Pi) vulnerabilities | 
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Mon, 03 Nov 2025 23:30:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| References | 
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Wed, 01 Oct 2025 21:15:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| Metrics | 
        
        ssvc
         
  | 
Wed, 16 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| Metrics | 
        
        
        epss
         
  | 
    
        
        
        epss
         
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Tue, 15 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| Metrics | 
        
        
        epss
         
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        epss
         
  | 
Wed, 14 May 2025 02:30:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9  | 
Tue, 04 Mar 2025 06:30:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| Weaknesses | CWE-476 | 
Wed, 19 Feb 2025 14:45:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| First Time appeared | 
        
        Redhat rhel Eus
         | 
|
| CPEs | cpe:/a:redhat:rhel_eus:9.4 | |
| Vendors & Products | 
        
        Redhat rhel Eus
         | 
Thu, 12 Dec 2024 02:15:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| First Time appeared | 
        
        Redhat
         Redhat enterprise Linux  | 
|
| CPEs | cpe:/a:redhat:enterprise_linux:8::nfv cpe:/o:redhat:enterprise_linux:8  | 
|
| Vendors & Products | 
        
        Redhat
         Redhat enterprise Linux  | 
Fri, 22 Nov 2024 14:00:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| References | 
         | |
| Metrics | 
        
        
        threat_severity
         
  | 
    
        
        
        threat_severity
         
  | 
Thu, 14 Nov 2024 18:30:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| First Time appeared | 
        
        Linux
         Linux linux Kernel  | 
|
| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:*  | 
|
| Vendors & Products | 
        
        Linux
         Linux linux Kernel  | 
|
| Metrics | 
        
        cvssV3_1
         
  | 
Sat, 09 Nov 2024 10:30:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6() I got a syzbot report without a repro [1] crashing in nf_send_reset6() I think the issue is that dev->hard_header_len is zero, and we attempt later to push an Ethernet header. Use LL_MAX_HEADER, as other functions in net/ipv6/netfilter/nf_reject_ipv6.c. [1] skbuff: skb_under_panic: text:ffffffff89b1d008 len:74 put:14 head:ffff88803123aa00 data:ffff88803123a9f2 tail:0x3c end:0x140 dev:syz_tun kernel BUG at net/core/skbuff.c:206 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 UID: 0 PID: 7373 Comm: syz.1.568 Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:skb_panic net/core/skbuff.c:206 [inline] RIP: 0010:skb_under_panic+0x14b/0x150 net/core/skbuff.c:216 Code: 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 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 RSP: 0018:ffffc900045269b0 EFLAGS: 00010282 RAX: 0000000000000088 RBX: dffffc0000000000 RCX: cd66dacdc5d8e800 RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000000 RBP: ffff88802d39a3d0 R08: ffffffff8174afec R09: 1ffff920008a4ccc R10: dffffc0000000000 R11: fffff520008a4ccd R12: 0000000000000140 R13: ffff88803123aa00 R14: ffff88803123a9f2 R15: 000000000000003c FS: 00007fdbee5ff6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000005d322000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> skb_push+0xe5/0x100 net/core/skbuff.c:2636 eth_header+0x38/0x1f0 net/ethernet/eth.c:83 dev_hard_header include/linux/netdevice.h:3208 [inline] nf_send_reset6+0xce6/0x1270 net/ipv6/netfilter/nf_reject_ipv6.c:358 nft_reject_inet_eval+0x3b9/0x690 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] br_nf_pre_routing_ipv6+0x63e/0x770 net/bridge/br_netfilter_ipv6.c:184 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_bridge_pre net/bridge/br_input.c:277 [inline] br_handle_frame+0x9fd/0x1530 net/bridge/br_input.c:424 __netif_receive_skb_core+0x13e8/0x4570 net/core/dev.c:5562 __netif_receive_skb_one_core net/core/dev.c:5666 [inline] __netif_receive_skb+0x12f/0x650 net/core/dev.c:5781 netif_receive_skb_internal net/core/dev.c:5867 [inline] netif_receive_skb+0x1e8/0x890 net/core/dev.c:5926 tun_rx_batched+0x1b7/0x8f0 drivers/net/tun.c:1550 tun_get_user+0x3056/0x47e0 drivers/net/tun.c:2007 tun_chr_write_iter+0x10d/0x1f0 drivers/net/tun.c:2053 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xa6d/0xc90 fs/read_write.c:683 ksys_write+0x183/0x2b0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdbeeb7d1ff Code: 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 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 1c 8e 02 00 48 RSP: 002b:00007fdbee5ff000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fdbeed36058 RCX: 00007fdbeeb7d1ff RDX: 000000000000008e RSI: 0000000020000040 RDI: 00000000000000c8 RBP: 00007fdbeebf12be R08: 0000000 ---truncated--- | |
| Title | netfilter: nf_reject_ipv6: fix potential crash in nf_send_reset6() | |
| References | 
         | 
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-11-03T22:27:36.148Z
Reserved: 2024-10-21T19:36:19.980Z
Link: CVE-2024-50256
Updated: 2025-10-01T15:25:22.516Z
Status : Modified
Published: 2024-11-09T11:15:11.263
Modified: 2025-11-03T23:17:07.083
Link: CVE-2024-50256
                        OpenCVE Enrichment
                    No data.
 Debian DLA
 Debian DSA
 Ubuntu USN