In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO
nf_osf_match_one() computes ctx->window % f->wss.val in the
OSF_WSS_MODULO branch with no guard for f->wss.val == 0. A
CAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a
subsequent matching TCP SYN divides by zero and panics the kernel.
Reject the bogus fingerprint in nfnl_osf_add_callback() above the
per-option for-loop. f->wss is per-fingerprint, not per-option, so
the check must run regardless of f->opt_num (including 0). Also
reject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that
as "should not happen".
Crash:
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98)
Call Trace:
<IRQ>
nf_osf_match (net/netfilter/nfnetlink_osf.c:220)
xt_osf_match_packet (net/netfilter/xt_osf.c:32)
ipt_do_table (net/ipv4/netfilter/ip_tables.c:348)
nf_hook_slow (net/netfilter/core.c:622)
ip_local_deliver (net/ipv4/ip_input.c:265)
ip_rcv (include/linux/skbuff.h:1162)
__netif_receive_skb_one_core (net/core/dev.c:6181)
process_backlog (net/core/dev.c:6642)
__napi_poll (net/core/dev.c:7710)
net_rx_action (net/core/dev.c:7945)
handle_softirqs (kernel/softirq.c:622)
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Linux |
|
No data.
No data.
No data.
References
History
Wed, 27 May 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO nf_osf_match_one() computes ctx->window % f->wss.val in the OSF_WSS_MODULO branch with no guard for f->wss.val == 0. A CAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a subsequent matching TCP SYN divides by zero and panics the kernel. Reject the bogus fingerprint in nfnl_osf_add_callback() above the per-option for-loop. f->wss is per-fingerprint, not per-option, so the check must run regardless of f->opt_num (including 0). Also reject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that as "should not happen". Crash: Oops: divide error: 0000 [#1] SMP KASAN NOPTI RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98) Call Trace: <IRQ> nf_osf_match (net/netfilter/nfnetlink_osf.c:220) xt_osf_match_packet (net/netfilter/xt_osf.c:32) ipt_do_table (net/ipv4/netfilter/ip_tables.c:348) nf_hook_slow (net/netfilter/core.c:622) ip_local_deliver (net/ipv4/ip_input.c:265) ip_rcv (include/linux/skbuff.h:1162) __netif_receive_skb_one_core (net/core/dev.c:6181) process_backlog (net/core/dev.c:6642) __napi_poll (net/core/dev.c:7710) net_rx_action (net/core/dev.c:7945) handle_softirqs (kernel/softirq.c:622) | |
| Title | netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-27T09:24:40.805Z
Reserved: 2026-05-13T15:03:33.078Z
Link: CVE-2026-45841
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-05-27T11:16:23.493
Modified: 2026-05-27T11:16:23.493
Link: CVE-2026-45841
Redhat
No data.
OpenCVE Enrichment
No data.