In the Linux kernel, the following vulnerability has been resolved:
vxlan: Fix nexthop hash size
The nexthop code expects a 31 bit hash, such as what is returned by
fib_multipath_hash() and rt6_multipath_hash(). Passing the 32 bit hash
returned by skb_get_hash() can lead to problems related to the fact that
'int hash' is a negative number when the MSB is set.
In the case of hash threshold nexthop groups, nexthop_select_path_hthr()
will disproportionately select the first nexthop group entry. In the case
of resilient nexthop groups, nexthop_select_path_res() may do an out of
bounds access in nh_buckets[], for example:
hash = -912054133
num_nh_buckets = 2
bucket_index = 65535
which leads to the following panic:
BUG: unable to handle page fault for address: ffffc900025910c8
PGD 100000067 P4D 100000067 PUD 10026b067 PMD 0
Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
CPU: 4 PID: 856 Comm: kworker/4:3 Not tainted 6.5.0-rc2+ #34
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:nexthop_select_path+0x197/0xbf0
Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85
RSP: 0018:ffff88810c36f260 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8
RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219
R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0
R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900
FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900025910c8 CR3: 0000000129d00000 CR4: 0000000000750ee0
PKRU: 55555554
Call Trace:
<TASK>
? __die+0x23/0x70
? page_fault_oops+0x1ee/0x5c0
? __pfx_is_prefetch.constprop.0+0x10/0x10
? __pfx_page_fault_oops+0x10/0x10
? search_bpf_extables+0xfe/0x1c0
? fixup_exception+0x3b/0x470
? exc_page_fault+0xf6/0x110
? asm_exc_page_fault+0x26/0x30
? nexthop_select_path+0x197/0xbf0
? nexthop_select_path+0x197/0xbf0
? lock_is_held_type+0xe7/0x140
vxlan_xmit+0x5b2/0x2340
? __lock_acquire+0x92b/0x3370
? __pfx_vxlan_xmit+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
? __pfx_register_lock_class+0x10/0x10
? skb_network_protocol+0xce/0x2d0
? dev_hard_start_xmit+0xca/0x350
? __pfx_vxlan_xmit+0x10/0x10
dev_hard_start_xmit+0xca/0x350
__dev_queue_xmit+0x513/0x1e20
? __pfx___dev_queue_xmit+0x10/0x10
? __pfx_lock_release+0x10/0x10
? mark_held_locks+0x44/0x90
? skb_push+0x4c/0x80
? eth_header+0x81/0xe0
? __pfx_eth_header+0x10/0x10
? neigh_resolve_output+0x215/0x310
? ip6_finish_output2+0x2ba/0xc90
ip6_finish_output2+0x2ba/0xc90
? lock_release+0x236/0x3e0
? ip6_mtu+0xbb/0x240
? __pfx_ip6_finish_output2+0x10/0x10
? find_held_lock+0x83/0xa0
? lock_is_held_type+0xe7/0x140
ip6_finish_output+0x1ee/0x780
ip6_output+0x138/0x460
? __pfx_ip6_output+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
? __pfx_ip6_finish_output+0x10/0x10
NF_HOOK.constprop.0+0xc0/0x420
? __pfx_NF_HOOK.constprop.0+0x10/0x10
? ndisc_send_skb+0x2c0/0x960
? __pfx_lock_release+0x10/0x10
? __local_bh_enable_ip+0x93/0x110
? lock_is_held_type+0xe7/0x140
ndisc_send_skb+0x4be/0x960
? __pfx_ndisc_send_skb+0x10/0x10
? mark_held_locks+0x65/0x90
? find_held_lock+0x83/0xa0
ndisc_send_ns+0xb0/0x110
? __pfx_ndisc_send_ns+0x10/0x10
addrconf_dad_work+0x631/0x8e0
? lock_acquire+0x180/0x3f0
? __pfx_addrconf_dad_work+0x10/0x10
? mark_held_locks+0x24/0x90
process_one_work+0x582/0x9c0
? __pfx_process_one_work+0x10/0x10
? __pfx_do_raw_spin_lock+0x10/0x10
? mark_held_locks+0x24/0x90
worker_thread+0x93/0x630
? __kthread_parkme+0xdc/0x100
? __pfx_worker_thread+0x10/0x10
kthread+0x1a5/0x1e0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x60
---truncated---
vxlan: Fix nexthop hash size
The nexthop code expects a 31 bit hash, such as what is returned by
fib_multipath_hash() and rt6_multipath_hash(). Passing the 32 bit hash
returned by skb_get_hash() can lead to problems related to the fact that
'int hash' is a negative number when the MSB is set.
In the case of hash threshold nexthop groups, nexthop_select_path_hthr()
will disproportionately select the first nexthop group entry. In the case
of resilient nexthop groups, nexthop_select_path_res() may do an out of
bounds access in nh_buckets[], for example:
hash = -912054133
num_nh_buckets = 2
bucket_index = 65535
which leads to the following panic:
BUG: unable to handle page fault for address: ffffc900025910c8
PGD 100000067 P4D 100000067 PUD 10026b067 PMD 0
Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
CPU: 4 PID: 856 Comm: kworker/4:3 Not tainted 6.5.0-rc2+ #34
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:nexthop_select_path+0x197/0xbf0
Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85
RSP: 0018:ffff88810c36f260 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8
RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219
R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0
R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900
FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900025910c8 CR3: 0000000129d00000 CR4: 0000000000750ee0
PKRU: 55555554
Call Trace:
<TASK>
? __die+0x23/0x70
? page_fault_oops+0x1ee/0x5c0
? __pfx_is_prefetch.constprop.0+0x10/0x10
? __pfx_page_fault_oops+0x10/0x10
? search_bpf_extables+0xfe/0x1c0
? fixup_exception+0x3b/0x470
? exc_page_fault+0xf6/0x110
? asm_exc_page_fault+0x26/0x30
? nexthop_select_path+0x197/0xbf0
? nexthop_select_path+0x197/0xbf0
? lock_is_held_type+0xe7/0x140
vxlan_xmit+0x5b2/0x2340
? __lock_acquire+0x92b/0x3370
? __pfx_vxlan_xmit+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
? __pfx_register_lock_class+0x10/0x10
? skb_network_protocol+0xce/0x2d0
? dev_hard_start_xmit+0xca/0x350
? __pfx_vxlan_xmit+0x10/0x10
dev_hard_start_xmit+0xca/0x350
__dev_queue_xmit+0x513/0x1e20
? __pfx___dev_queue_xmit+0x10/0x10
? __pfx_lock_release+0x10/0x10
? mark_held_locks+0x44/0x90
? skb_push+0x4c/0x80
? eth_header+0x81/0xe0
? __pfx_eth_header+0x10/0x10
? neigh_resolve_output+0x215/0x310
? ip6_finish_output2+0x2ba/0xc90
ip6_finish_output2+0x2ba/0xc90
? lock_release+0x236/0x3e0
? ip6_mtu+0xbb/0x240
? __pfx_ip6_finish_output2+0x10/0x10
? find_held_lock+0x83/0xa0
? lock_is_held_type+0xe7/0x140
ip6_finish_output+0x1ee/0x780
ip6_output+0x138/0x460
? __pfx_ip6_output+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
? __pfx_ip6_finish_output+0x10/0x10
NF_HOOK.constprop.0+0xc0/0x420
? __pfx_NF_HOOK.constprop.0+0x10/0x10
? ndisc_send_skb+0x2c0/0x960
? __pfx_lock_release+0x10/0x10
? __local_bh_enable_ip+0x93/0x110
? lock_is_held_type+0xe7/0x140
ndisc_send_skb+0x4be/0x960
? __pfx_ndisc_send_skb+0x10/0x10
? mark_held_locks+0x65/0x90
? find_held_lock+0x83/0xa0
ndisc_send_ns+0xb0/0x110
? __pfx_ndisc_send_ns+0x10/0x10
addrconf_dad_work+0x631/0x8e0
? lock_acquire+0x180/0x3f0
? __pfx_addrconf_dad_work+0x10/0x10
? mark_held_locks+0x24/0x90
process_one_work+0x582/0x9c0
? __pfx_process_one_work+0x10/0x10
? __pfx_do_raw_spin_lock+0x10/0x10
? mark_held_locks+0x24/0x90
worker_thread+0x93/0x630
? __kthread_parkme+0xdc/0x100
? __pfx_worker_thread+0x10/0x10
kthread+0x1a5/0x1e0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x60
---truncated---
Metrics
Affected Vendors & Products
No data.
No data.
No data.
No data.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Mon, 15 Sep 2025 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: vxlan: Fix nexthop hash size The nexthop code expects a 31 bit hash, such as what is returned by fib_multipath_hash() and rt6_multipath_hash(). Passing the 32 bit hash returned by skb_get_hash() can lead to problems related to the fact that 'int hash' is a negative number when the MSB is set. In the case of hash threshold nexthop groups, nexthop_select_path_hthr() will disproportionately select the first nexthop group entry. In the case of resilient nexthop groups, nexthop_select_path_res() may do an out of bounds access in nh_buckets[], for example: hash = -912054133 num_nh_buckets = 2 bucket_index = 65535 which leads to the following panic: BUG: unable to handle page fault for address: ffffc900025910c8 PGD 100000067 P4D 100000067 PUD 10026b067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI CPU: 4 PID: 856 Comm: kworker/4:3 Not tainted 6.5.0-rc2+ #34 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:nexthop_select_path+0x197/0xbf0 Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85 RSP: 0018:ffff88810c36f260 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77 RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8 RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219 R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0 R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc900025910c8 CR3: 0000000129d00000 CR4: 0000000000750ee0 PKRU: 55555554 Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x1ee/0x5c0 ? __pfx_is_prefetch.constprop.0+0x10/0x10 ? __pfx_page_fault_oops+0x10/0x10 ? search_bpf_extables+0xfe/0x1c0 ? fixup_exception+0x3b/0x470 ? exc_page_fault+0xf6/0x110 ? asm_exc_page_fault+0x26/0x30 ? nexthop_select_path+0x197/0xbf0 ? nexthop_select_path+0x197/0xbf0 ? lock_is_held_type+0xe7/0x140 vxlan_xmit+0x5b2/0x2340 ? __lock_acquire+0x92b/0x3370 ? __pfx_vxlan_xmit+0x10/0x10 ? __pfx___lock_acquire+0x10/0x10 ? __pfx_register_lock_class+0x10/0x10 ? skb_network_protocol+0xce/0x2d0 ? dev_hard_start_xmit+0xca/0x350 ? __pfx_vxlan_xmit+0x10/0x10 dev_hard_start_xmit+0xca/0x350 __dev_queue_xmit+0x513/0x1e20 ? __pfx___dev_queue_xmit+0x10/0x10 ? __pfx_lock_release+0x10/0x10 ? mark_held_locks+0x44/0x90 ? skb_push+0x4c/0x80 ? eth_header+0x81/0xe0 ? __pfx_eth_header+0x10/0x10 ? neigh_resolve_output+0x215/0x310 ? ip6_finish_output2+0x2ba/0xc90 ip6_finish_output2+0x2ba/0xc90 ? lock_release+0x236/0x3e0 ? ip6_mtu+0xbb/0x240 ? __pfx_ip6_finish_output2+0x10/0x10 ? find_held_lock+0x83/0xa0 ? lock_is_held_type+0xe7/0x140 ip6_finish_output+0x1ee/0x780 ip6_output+0x138/0x460 ? __pfx_ip6_output+0x10/0x10 ? __pfx___lock_acquire+0x10/0x10 ? __pfx_ip6_finish_output+0x10/0x10 NF_HOOK.constprop.0+0xc0/0x420 ? __pfx_NF_HOOK.constprop.0+0x10/0x10 ? ndisc_send_skb+0x2c0/0x960 ? __pfx_lock_release+0x10/0x10 ? __local_bh_enable_ip+0x93/0x110 ? lock_is_held_type+0xe7/0x140 ndisc_send_skb+0x4be/0x960 ? __pfx_ndisc_send_skb+0x10/0x10 ? mark_held_locks+0x65/0x90 ? find_held_lock+0x83/0xa0 ndisc_send_ns+0xb0/0x110 ? __pfx_ndisc_send_ns+0x10/0x10 addrconf_dad_work+0x631/0x8e0 ? lock_acquire+0x180/0x3f0 ? __pfx_addrconf_dad_work+0x10/0x10 ? mark_held_locks+0x24/0x90 process_one_work+0x582/0x9c0 ? __pfx_process_one_work+0x10/0x10 ? __pfx_do_raw_spin_lock+0x10/0x10 ? mark_held_locks+0x24/0x90 worker_thread+0x93/0x630 ? __kthread_parkme+0xdc/0x100 ? __pfx_worker_thread+0x10/0x10 kthread+0x1a5/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x60 ---truncated--- | |
| Title | vxlan: Fix nexthop hash size | |
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-09-15T14:06:37.241Z
Reserved: 2025-09-15T13:59:19.066Z
Link: CVE-2023-53192
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2025-09-15T14:15:41.523
Modified: 2025-09-15T15:22:27.090
Link: CVE-2023-53192
Redhat
No data.
OpenCVE Enrichment
No data.