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CVE-2026-45841

netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO PUBLISHED

Description (CNA)

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)

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before cb833bbc1b3c51e08652d3c86298307c07d3f2db; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 26900306a5a2c3e4f75c643a064525526bb6e5f3; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 0694618cf3e9b120666e31f5f383a6e466d95a0d; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 8def8fbd23f40e945febe913d04b731012ce0082; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before c55940895245d8ef658ab381248a28755218d625; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 9a05e195618a6d474f2bcd5b6376d0ffc2f00366; affected 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 2195574dc6d9017d32ac346987e12659f931d932
Linux / Linuxaffected 2.6.31; unaffected 0 before 2.6.31; unaffected 5.10.258 through 5.10.*; unaffected 5.15.209 through 5.15.*; unaffected 6.1.175 through 6.1.*; unaffected 6.6.141 through 6.6.*; unaffected 6.12.91 through 6.12.*; unaffected 6.18.33 through 6.18.*; unaffected 7.0.10 through 7.0.*; unaffected 7.1 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

siemens-SADP

No English description supplied.